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PERSPECTIVES|Volume 7/ Issue 1

MITA (P) 002/05/2004 • ISSN 0219-1830 • Vol. 7/ Issue 1 • 1st Quarter 2005Research, Development and Commercialisation

CONTENTS

PAGE 1PERSPECTIVES + IMPACT -A New Perspective!

PAGE 2 - 3SPECIAL FEATURE

- IMRE’s R&D – BeyondEnabling Technology

PAGE 4 - 7CORPORATE NEWS

- Another Renowned ScientistJoins IMRE Under A*STAR’sVIP Scheme

- Tapping on Central EuropeanR&D Expertise

- IMRE’s Role as a MaterialsScience and CharacterisationResearch Hub

- ICES-IMRE-Mitsui Master R&DAgreement Signed

- IMRE Conducts Training forSingapore’s OLED Manufacturers

PAGE 7Visitors & Events (Sep - Dec 04)

PAGE 8 - 9Patents Filed and Granted

PAGE 10 - 12RESEARCH

- Optical Tuning and Coupling inInP-based Photonic Devices

- InAs Self-assembled QuantumDots for Photonic Devices

- Quantum Dot Intermixing forMonolithic Photonic Integration

PAGE 12Upcoming Seminars / Workshops /Symposia (Jan – Mar 2005)

Dear Readers!

Greetings and a Happy New Year!

IMRE’s Corporate Communications

would like to take this opportunity to thank

you, our loyal readers, for your support of

our newsletters. As most of you know, we

currently have two printed publications,

PERSPECTIVES (corporate news – thrice-yearly issue) and IMPACT (research-related

news – quarterly issue) as well as an e-newsletter, IMRe-news.

Starting with this issue we will be combining the two printed newsletters into a

quarterly issue, to give you a holistic view about the happenings in IMRE, both from

a corporate and a research perspective. We will be retaining the title

“PERSPECTIVES” for this combined newsletter.

The IMRe-news will continue in its present form and on a bimonthly basis.

We look forward to your continued support of our newsletters!

PERSPECTIVES + IMPACT -

A New Perspective!A New Perspective!IMRE Newsletters ata Glance• Perspectives - Quarterly

• IMRe-news - Bimonthly

Past issues of our newslettersare available on our website

at www.imre.a-star.edu.sgP/S: Please feel free to drop us a line ([email protected]) if you haveany queries about our publications or any of the articles that interest you!


2 IMRE

Special Feature

We take a look at some of the technologies developed by IMRE and their potential applications inthe marketplace.

Since it’s inception in 1996, the process of research, re-invention and innovation has been in full swing in IMRE. And in thattime, IMRE has achieved significant milestones in R&D, including the setting-up of one of the best-equipped and well staffedcharacterisation facilities in the region, pioneering local R&D work on organic light emitting devices as well as fuel celltechnology. Following are some of our most recent breakthroughs:

IMRE’s R&D -Beyond Enabling Technology

Anti-counterfeiting Nano-sized Magnetic Tags

TechnologySingular ID – Nano-sized Magnetic Fingerprint TechnologyIMRE’s Singular ID was a finalist in the Far Eastern Economic Review’s Asian Innovation Awards 2004. The Award isAsia’s premier honour for individuals and companies who come up with new ideas, methods or technologies, or applyexisting knowledge in creative, new ways to improve the quality of life or enhance productivity.

DescriptionSingular ID uses nanotechnology to create low-cost magnetic labels that have ‘unique’ fingerprints. These labels areprohibitively difficult to replicate, can be invisible to the naked eye, lightweight and resilient in extreme environmentalconditions. The labels can also be mass-produced inexpensively.

Uniqueness / Advantage• Inexpensive tags• Unique randomised structure as each tag is different and virtually impossible to reproduce• Readable with existing equipment such as standard magnetic read heads• Tags can be made extremely small (the width of a human hair), so they can be overt or covert• Tags are thermally and chemically stable and, with an additional coating, are mechanically robust• Cannot be detected remotely thus preventing Singular ID tags from being located and removed, unlike radio

frequency (RF) tags.• Not adversely affected by external magnetic fields

Potential Applications• Identification and authentication markers to prevent fraud• Secure logistical and inventory tracking• Invisible labels for precious articles such as jewellery• Tamper-proof passports, identification cards, security

passes, etc.• Prevent pirating of goods such as audio and video CDs

Highlights• Finalist in the Far Eastern Economic Review Asian

Innovation Awards 2004• Second Prize in the 8th Edition of The Roland Berger

- INSEAD Business Plan Competition 2004

Contact• Dr Peter Moran ([email protected])• Dr Adrian Burden ([email protected])

Website• www.imre.a-star.edu.sg/singular-id

Presidential Audience - Dr Adrian Burden briefing the President of theRepublic of Singapore, Mr S. R. Nathan, about IMRE’s unique magnetictagging technology at the Asian Innovation Awards 2004 ceremony.

PERSPECTIVES|Volume 7/ Issue 1 Special Feature

IMRE

Fluidlens - Mini Liquid Optical LensThat Allows Optical Zoom Feature

Fluidlens (above left)greatly reduces the size ofoptical systems and allowsoptical zoom.

For more information, or if you are interested in the licensing and commercialisation of these technologies, please contactIMRE’s Business Development Office at [email protected]

Microneedles present theoption of painless injections.

Images of radius ofcurvature variationwith pressure for a2 mm plano-convexliquid lenses.

3

TechnologyMicroneedlesDescriptionA novel miniature medicaldevice for subcutaneousdrug delivery using amicroneedle array. Thesemicroneedles will penetratethe stratum corneum (thetopmost layer of the skin),which is the major barrierthat prevents particles, including drug molecules, frompenetrating the skin. The short length of themicroneedle restricts the penetration depth to thesecond layer of the skin or the viable epidermis. Thislayer contains living cells but few blood vessels andnerves, thus making drug delivery efficient andrelatively painless. Current microneedles are either toobrittle (silicon and glass micro needles) or too soft(polymer microneedles) and costly.

Uniqueness / Advantage• Low cost• Wide range of dimensions (100-2000 micron in

length and 50 to 1000 micro in diameter)• Several different cross section shapes available• Suitable for mass production

Potential Applications• Painless drug delivery injections• Genetic engineering (injecting DNA into cells)• Precise and controlled dispensing of chemical

agents in analytical instruments• Assist in ball grid array assembly in semiconductor

industry

Highlights• Featured in Channel NewsAsia, “Singapore

Tonight” segment, 18 June 2004• Featured in Lianhe Zaobao, 27 May 2004

Contact• Mr Lim Chee Yen ([email protected])

TechnologyFluidlensDescriptionA miniature optical lens thesize of a one-cent coin thatuses water contained influidic reservoirs to achievedynamic focusing. The lens

has a 3mm - ∞ focal range and 10x zoom featurewithin the 1.5 x 1.5 cm2 packaged focusing system.Fluidlens mimics the focusing mechanism of thehuman eye by changing the radius of curvature at theliquid-air interface, hence adjusting the focal length.Fluidlens is particularly useful in compact, smalloptical devices, where a non-mechanical focusingapproach with the least moving parts is preferredbecause of the limitations of space and size.

Uniqueness / Advantage• Low cost - estimated at less than a dollar in

mass production• Miniature in size - 1.5 x 1.5 cm2 package with

room to go smaller• Wide focal range (3mm - ∞) for focusing on both

near and distant objects• Scratch-resistant as opposed to normal plastic

and glass lenses

Potential Applications• Telecommunications - Optical switches, fibre optic

coupling, mobile phone cameras, webcams• Data storage - CD, DVD, blue

ray DVD-type drivers,barcode readers

• Analytical equipment -Portable microscopes, sensors

• Manufacturing - Lasertechnology

• Medicine - Endoscopes• Military applications

Highlights• Featured in The New Paper,

26 September 2004

Contact• Dr Saman Dharmatilleke

([email protected])• Dr Isabel Rodriguez

([email protected])

Micro-sized Needles for Painless Injections


Profile –Professor Ananth Dodabalapur

Professor Ananth Dodabalapur’sresearch experience and credentialsspeak volumes about his expertise. Aprofessor with The University of Texasat Austin’s Electricaland ComputerEngineeringdepartment, he hasreceived numerous

accolades for his research work. Most notablewas his research on organic transistor circuitswhich was cited by Science Magazine as one ofthe top 10 scientific breakthroughs for the year2000.

At 41, he has published over 100 articles inrefereed journals and has more than 30 U.S.patents issued or pending office action. He is aco-recipient of the 2002 Award for TeamInnovation of the American Chemical Society,and a co-recipient of an R&D 100 Award for2001.

Since 1992 Prof Dodabalapur hasinvestigated various aspects of the physics and technology oforganic and polymer semiconductor devices. His currentinterests are organic transistors, organic-based chemical andbiological sensors, and organic-based laser physics andoptics.

Outside of research, Prof Dodabalapur is a self-confessednature-lover who is always on the lookout for a good jungleto trek, even if they do involve being chased by wildelephants and a lot of running (in his younger days, as heputs it!).

What is the importance/impact of the projectthat you are doing under the VIP scheme?

As part of the VIP scheme, I will be working closely withresearchers like Dr Alan Sellinger and Dr Chen Zhikuan onMolecular and Polymer Electronics focusing on Organic SolarCells and Organic Thin Film Transistors. This researchwill involve synthesizing new materials all the way tofabricating functional devices, with a team made up ofchemists, physicists and engineers.

There are a lot of exciting things happening now in thefield of organic electronics. These occurrences happen onlyat certain periods in the evolution of a particulartechnology. For this reason, setting up a coordinatedresearch effort in NTU, NUS and A*STAR’s IMRE is anexcellent opportunity to produce good quality research in

Another Renowned Scientist Joins IMRE UnderA*STAR’s Visiting Investigatorship Programme (VIP)Professor Ananth Dodabalapur whose research on organic transistor was cited as one of the top 10 scientificbreakthroughs for the year (Science Magazine – 2000) joins IMRE under the Visiting InvestigatorshipProgramme (VIP).

A*STAR’s VisitingInvestigatorship Programme

The programme is a prestigious three-year appointmentfor high calibre scientists with excellent academic andresearch credentials. It aims to:

• Attract foreign talent for participation in our localscientific capabilities development

• Provide expertise for RIs to leverage on

• Strengthen our links with the international researchcommunity

A good researcher

must have a passion

for the work that he

or she is doing. So

much so that they

would constantly

think about it, and be

absorbed by it, any

time, anywhere!

organic electronics. The quality of research andinfrastructure in IMRE and the universities are very goodand I am looking forward to having more colleagues as keypotential collaborators.

As a distinguished and experienced researcher,what do you think are some of the qualitiesthat make a good scientist?

One of the most important qualities thatmark a good scientist is passion! A goodresearcher must have a passion for the workthat he or she is doing. So much so that theywould constantly think about it, and beabsorbed by it, any time, anywhere!

What do you do in your spare timewhen you are not doing research?

When I have spare time, I’m still thinkingof research! That’s what I mean when Imentioned having a passion for your work.The research just becomes second nature toyou.

Speaking of nature, I do love trekkingand exploring as well, which probably goesback to my younger days when I used toexplore jungles with my friends. When I wasa teenager, I remember a school project to

find out the scientific names of the all the trees on my schoolcampus - my first brush with research work. You could saythen that nature and research have been a big part of mylife since an early age.

Do you have any words of advice for buddingscientists?

For those thinking about research as a career I wouldadvise to find out first about the area of research that youintend to pursue. The ‘fit’ has to be good. Only then canpassion and commitment to the research work grow.

4 IMRE

Corporate News


A*STAR’s Science andEngineering ResearchCouncil (SERC)conducted the first everA*STAR-Central EuropeWorkshop in IMRE toestablish potential futureR&D cooperation withscientists from the region.Held from 18 - 19November 2004, theworkshop focused on

topics in “Chemistry & Materials”, bringing together localresearchers and some 34 Central European scientists fromHungary, Poland and the Czech Republic.

Tapping on CentralEuropean R&D ExpertiseJoint workshop hopes to incubate potentialpartnerships between local and Central Europeanresearchers.

Dr Lim Khiang Wee, who is also theDeputy Executive Director ofA*STAR’s SERC, giving an overviewat the start of the workshop.

The aim of the event was to promote scientific co-operation and use the workshop as a platform for mutualexchange as well as showcase of R&D capabilities that willenable participating scientists to explore possible areas ofresearch collaboration. Local postdoctoral researchers andPhD students nearing completion of their thesis were alsoinvited to attend the workshop.

”This Workshop will hopefully serve as a stepping stonefor future R&D cooperation between local scientists and thosefrom the Central European region,” said Dr Lim Khiang Wee,IMRE’s Executive Director. “The region has a very well-established R&D history and infrastructure that researchersand engineers here can tap on”.

(Left) Participants of the workshop in discussion during the postersession and (Right) Some of the speakers taking a closer look atIMRE’s characterisation capabilities during a tour.

With an array of high-tech, state-of-the-artcharacterisation facilities, and an experienced and highly-qualified research team, IMRE’s characterisation laboratory isone of the most comprehensive in Singapore, making it anobvious choice to be a hub for SERC’s scientificcharacterisation studies.

In line with this, IMRE’s characterisation team has beenactively marketing its strengths in characterisation to its sisterresearch institutes (RIs). IMRE recently conducted a series ofpresentations on its equipment and research capabilities tocreate an awareness of how RIs can leverage on IMRE’s well-established characterisation infrastructure.

Said Dr Emma Philpott, Business Manager with IMRE’sMaterials Science and Characterisation Laboratory (MSCL),“Our team aims to provide high quality materialscharacterisation and advice to all RIs and Industry. We focusheavily on the provision of advice and discussion of the widerissues surrounding the characterisation. We put the analysis

results into context andhelp explain what theresults may mean inpractical terms”.

Dr Philpott adds thatthe team continuallyconducts research intoadvancedcharacterisationtechniques, which helpskeep IMRE at the forefront

IMRE’s Role as a Materials Science andCharacterisation Research HubExpertise and vast experience in materials science and characterisation research makes IMRE an obviouschoice for the characterisation studies hub for A*STAR’s SERC.

of characterisationtechnology.

Apart from the RIsand tertiaryinstitutions, thecharacterisation teamhas been activelyengaged in providingconsultancy support tolocal industry on amyriad ofcharacterisation issuesand research studies.

For more information on the Materials Science andCharacterisation (MSC) Laboratory, please contact Dr EmmaPhilpott at [email protected].

Participants being briefed on IMRE’scharacterisation capabilities.

Dr Emma Philpott introducing theMaterials Science and Characterisationlaboratory to attendees.

Some of the characterisation equipment andcapabilities available in IMRE:• XPS/UPS• TOF-SIMS/Dynamic SIMS• TEM/SEM/FIB• NMR/Chemical analysis• Mechanical Testing• X-ray analysisFor more information, you can download our MaterialsScience and Characterisation (MSC) equipmentbrochure from our website at www.imre.a-star.edu.sg

5 IMRE

Corporate News


A*STAR and Mitsui Chemicals, Inc., one of the largestchemical companies in Japan, signed a master R&Dagreement for joint research collaboration. A*STAR’s R & Dcapability is represented by IMRE and the Institute ofChemical and Engineering Sciences (ICES).

The master agreement, sealed on 16 September 2004,paves the way for researchers, scientists and engineers fromIMRE, ICES and Mitsui to collaborate on R&D projects todevelop proprietary products, process technologies as well asjointly publish patents and scientific papers.

“A*STAR’s collaborative alliance with Mitsui Chemicalsrepresents a win-win partnership to meeting the challenge ofbringing new skills and technologies to the chemicalscluster,” mentioned Prof Chong Tow Chong, ExecutiveDirector of the Science and Engineering Research Council,A*STAR, who was on hand to witness the signing ceremony.

Mitsui’s R&D collaboration with IMRE leverages on theInstitute’s strength and capabilities in materials design,synthesis and characterisation expertise. IMRE will work withMitsui to discover new product applications through thedevelopment of nano-structured hybrid materials.

Commented Prof Chua Soo Jin, IMRE’s Deputy Executive

IMRE Conducts Training for Singapore’sOLED ManufacturersThe Institute’s many years of experience and expertise in OLED technology serves as the platform for itsOLED technical and practical training.

Director, “IMRE hasbeen working onnano-structured hybridmaterials and thiscollaboration withMitsui Chemicals willallow us to exploretheir potentials forindustrial application”.

In kick-starting thecollaboration, a minijoint-symposium onMaterials Research was

held in IMRE and the delegates from Mitsui, led by Dr AkihiroYamaguchi, Managing Director and Group Executive, R&DCentre, Mitsui Chemicals, Inc., took the opportunity to visitthe laboratories of ICES and IMRE.

The chemicals industry in Singapore registered anincrease of 23% in output and 9% in value-add to S$39.1billion and S$5.2 billion respectively in 2003, despite thechallenges of rising prices of raw materials and high energycosts globally.

The visitors from Mitsui speaking toIMRE scientists in the Materials Scienceand Characterisation Laboratory duringa tour of IMRE’s facilities.

As part of the Institute’s effort to lead and support thegrowth of the Organic Light-Emitting Diode (OLED) displayindustry in Singapore, IMRE has developed an industry-focused training programme that aims to equip localengineers with fundamental knowledge of OLED technology.

The programme conducted over six half-days consists of aseries of lectures and hands-on practical training in the

Institute’s OLED laboratories, and allows participants theopportunity to develop the necessary understanding in theresearch, development and manufacturing of OLED devices.

The first company to benefit from the training programmewas Innoled Pte Ltd, a subsidiary of the Singapore-listedcompany Eastgate Technology Ltd. Mr Peter Karlsson,Managing Director of Innoled said, “We are extremely gladthat IMRE has decided to conduct an OLED-focused trainingprogramme. With IMRE’s experience and knowledge inpolymeric OLED, the programme was very helpful inaddressing our company’s training needs as we embark tobecome the first OLED manufacturer in Singapore using theconjugated polymer technology.”

In order to derive maximum benefit, IMRE undertook aconsultative approach to identify the companies’ specificneeds beforehand so as to tailor the training programme tomeet their requirements. Dr Kim Shin Cheul, Ness Display’sManufacturing Director noted, “We are very pleased to beable to send all our 25 new engineers for training in IMREprior to their attachment with Ness Display Co., Ltd. in SouthKorea. To have part of the training in Singapore helps us toreduce the training time and accelerate the process ofbuilding up our mass production facility in Singapore.”

IMRE’s very established OLED research and development teamconducting one of the technical training sessions.

6 IMRE

ICES-IMRE-Mitsui Master R&DAgreement SignedICES-IMRE-Mitsui Master R&DAgreement SignedIMRE and Mitsui in joint collaboration deal to develop proprietary products and processes.

Corporate News


Dr Adrian Burden,IMRE’s SeniorResearch Engineerfurther explained,“With the expertisegained through ourOLED researchactivities over the lastsix years, IMRE is nowin a good position toimpart knowledge andexpertise in this field to

local industry. The training programme is an ideal platform toenable the Institute to establish a closer relationship with keylocal players in the OLED industry, which we believe will also

The OLED training consists not only oflectures but hands-on practical sessionsas well.

lead to possibilities for future collaboration in thedevelopment of new OLED technology.”

IMRE is also leading the OLED Network of Singapore(ON-Singapore) that seeks to promote and facilitate theresearch, development and manufacturing of OLEDs inSingapore. It provides the link between the local and theinternational OLED community. ON-Singapore currently has31 local and foreign Corporate Members, including Innoledand Ness Display.

Science 04 Exhibition3-5 September 2004As part of the month-longScience 04 event, the X-periment Exhibition was held atSuntec City. The exhibition isan annual event aimed atcreating public awareness

about Singapore’s scientific research. IMRE set up a booth toshowcase some of its research to the public. A separateevent, entitled “Trails & Tales of RIs”, was held on 10September 2004 in conjunction with Science 04, where JuniorCollege students experienced research close-up duringlaboratory tours organised at IMRE.

IMRE IndustrySymposium24 September 2004IMRE gave an introduction ofits research advancements,capabilities and facilities toinvited members of industry ina symposium aimed atfostering interaction and

potential collaboration between industry and our researchers.The symposium included presentations on the variousresearch areas, their highlights, research achievements andlaboratory tours.

IMRE-ICES JointSeminar6 October 2004An IMRE-ICES Joint Seminarwas held in IMRE in an effortto increase interaction betweenresearchers from both institutesas well as those from sister RIs.

The research developments and updates presented during theevent included work on fuel cells, poly(aralkyl ketone)s,nanoimprinted functionalised polymers, nano- and meso

porous materials, nanocomposite dendrimers for OLEDs,organo-clays, and hybrid organic-inorganic nanocomposites.Some 68 researchers from A*STAR Research Institutesattended the symposium.

MSC MechanicalTesting Workshop4 November 2004The Materials Science andCharacterisation Laboratory(MSCL) organised aMechanical Testing Workshopin partnership with the Germancompany Zwick/Roell, one of

the market-leading manufacturers of mechanical testingsystems. Participants from the semiconductor, electronics andmanufacturing sectors as well as tertiary and research institutesattended the workshop. Presentations included the applicationsof mechanical testing and materials modelling and examplesIMRE’s successes in this area. The workshop also served as aplatform for the Asian premier of Zwick’s new extensometer.

IMRE-NUS ChemistryDepartment JointSymposium25 November 2004A joint symposium organisedby IMRE and the Departmentof Chemistry at NUS broughttogether researchers from both

institutions to foster greater R&D exchange and to facilitatenetworking. The biennial event serves as a platform topromote research relationships, collaboration and student co-development programmes between IMRE and NUS. Theresearch topics discussed included synthesis andcharacterisation of functional polymers, nano-structuredmaterials, nano-composites, and their applications inoptoelectronics. Other topics were on nano/micro-systems forreactors and sensors, surface and interface investigationthrough microscopy as well as spectroscopy techniques.

7 IMRE

Visits and EventsVisits and EventsVisits and EventsVisits and Events(September - December 2004)

Corporate News/Visits & Events

For more information about the training programme and about ON-Singapore (www.imre.a-star.edu.sg/on-singapore), please contact:

Mr Colin LeongBusiness Development [email protected]

Eager young visitors at Science04.

An IMRE researcher giving anintroduction about IMRE’s fuelcell technology.

IMRE-ICES Joint Seminar insession.

Workshop participants touringIMRE’s characterisationfacilities.

Participants arriving for theSymposium.


8 IMRE

Patents

Method and apparatus for formingmicrostructuresThe invention relates to a method of transdermal drugdelivery using microneedles. The microneedles arefabricated using microforming technology withdeformable die. The method is inexpensive and suitablefor mass production. Potential applications of themicroneedles, usually in the form of arrays, includeadministration of drugs into a living organism orextraction of body fluids from it.Inventors: Lim Chee Yen, Xu Yuan, Hbaieb Kais, Tan YuanLing, ChristinaDate filed: 19 Nov 04Country filed: Patent Cooperation Treaty (PCT)

Poly(arylenevinylene) andpoly(heteroarylenevinylene) light emittingpolymers and polymer light-emitting devicesThe invention involves conjugated polymeric materials,their preparation methods, and their application inpolymer light-emitting diodes. The structural defects in thepolymers were drastically reduced, thereby increasing thedevice efficiency and lifetime of the light-emittingmaterials and devices. The proposed polymers can beused as the emissive layer for polymer light-emittingdiodes and can be fabricated into LED devices throughsolution process.Inventors: Chen Zhikuan, Huang ChunDate filed: 1 Nov 04Country filed: Patent Cooperation Treaty (PCT)

Multicolour organic light-emitting devicesThe invention describes the use of an organicelectroluminescent (EL) stack sandwiched by two electrodesto form a microcavity for colour tuning and efficiencyenhancement. The invention can be used for making a fullcolour pixelated display by adjusting the thickness of theinterposed transparent conducting oxide (TCO) to meet therequired microcavity condition for RGB.Inventors: Zhu Furong, Ong Kian Soo, Hao Xiao TaoDate filed: 11 Oct 04Countries filed: Taiwan

Flexible electroluminescent devicesThe invention describes a flexible PLED/OLED consistingof a top-emitting PLED/OLED on an opaque flexiblesubstrate. The top-emitting PLEDs/OLEDs include a thinelectron injector/a conducting metal layer/an indexmatching layer or a semitransparent metal cathode/anindex matching layer. The invention would haveapplications in mobile phone devices, PDAs, lighting, etc.Inventors: Zhu Furong, Ong Kian Soo, Hao Xiao TaoDate filed: 11 Oct 04Country filed: Taiwan

Device and method of detecting mutationsand polymorphisms in DNAThe invention relates to a method for detecting mutations

in DNA involving as little as one base change or a singlebase addition to, or deletion from the wild-type DNAsequences with the use of resonator sensors. The methodis useful for diagnosing a variety of disease states orsusceptibilities and detecting the presence of a mutatedoncogene.Inventors: Su Xiaodi, Robelek Rudolf, Wolfgang Knoll, SeanO’SheaDate filed: 22 Sep 04Countries filed: Singapore and US

A sensorThe invention involved a method for combining surfaceplasmon resonance (SPR) and quartz crystalmicrobalance (QCM) function in one device usingattenuated total reflection (ATR) based couplingtechniques for SPR measurement. The complementarysignals acquired by the combined device allow one totake advantage of the strengths of each function whiletesting the validity of some of the assumptions inherent indata analysis, thus gaining a more completeunderstanding of the interfacial phenomena studied.Inventors: Wang Guangyu, Su Xiaodi, Wolfgang Knoll, WuYing JuDate filed: 15 Sep 04Countries filed: Patent Cooperation Treaty (PCT)

An imprinted polymer supportThe invention describes a method to fabricate a NanoImprinted Modular Support (NIMS) for solid phaseorganic synthesis (SPOS) by taking advantage of thenanoimprint technique. The imprinted structure, NIMS,offers advantages that are not easily if not impractical toachieve through currently available technology. NIMSallows a great deal of design freedom to obtainimproved performance for modular support systems.Inventors: Low Hong Yee, Suresh ParappuveetilSarangadharan, Karen Darmono, Kong Yen PengDate filed: 15 Sep 04Country filed: Patent Cooperation Treaty (PCT)

Nanostructures and method of making thesameThe invention relates to an integrated fabricationprocess for ordered semiconductor nanostructures on apatterned substrate surface whereby the orderednanopatterns from a porous template is transferred to amask-film followed by a selective growth of thesemiconductor in a material deposition system. Theinvention could be used for the fabrication ofsemiconductor-based low-dimensional optoelectronicand microelectronic devices.Inventors: Chua Soo Jin, Chen Peng, Wang YadongDate filed: 31 Aug 04Countries filed: Patent Cooperation Treaty (PCT)

Reversal imprint techniqueThe invention involves a new imprinting technique thatavoids the need to spin-coat polymer layers on thesubstrate. A polymer layer was spin-coated directly on amould, and transferred to a substrate by imprinting under

Patents FiledPatents Filed

PERSPECTIVES|Volume 7/ Issue 1 Patents

9 IMRE

suitable temperature and pressure conditions.Inventors: Bao Lirong, L Jay Guo, Albert Yee, HuangXudong, Stella Pang, Chen XingDate filed: 8 May 02 (PCT filing date)Countries filed: US, Germany, Singapore, Japan

Method for electroless deposition of a metallayer on selected portions of a substrateThis invention provides a method for selectivelymetallising ceramic, metal or polymer substrates. It allowssimple, accurate patterning on the microscale.Inventors: Sunil Madhukar Bhangale, Li Zhongli, Peter MoranDate filed: 23 Apr 03 (PCT filing date)Country filed: Japan

Method for forming a modified semiconductorhaving a plurality of band gapsThis invention provides a simple and effective method forspatially selective post-growth tuning of the transition

energy levels of a semiconductor heterostructure and amethod for multi-level (>4) transition energy tuningacross a single wafer.Inventors: Teng Jinghua, Dong Jianrong, Chua Soo JinDate filed: 4 Apr 03 (PCT filing date)Country filed: US

Microneedles and microneedle fabricationThe invention describes several methods for fabricatingtapered (or straight) hollow microneedles. These methodscan be used to make metallic needles with sufficientstrength and ductility. The invention has the advantagethat the fabrication cost is lower than those techniquesreported in literature and has potential application fortransdermal drug delivery.Inventors: Xu Yuan, Chen Meima, Li Zhongli, Lim CheeYen, Tan Pei YingDate filed: 10 Nov 03 (PCT filing date)Country filed: Japan

A process for modifying chip substrateassembliesThis invention is a method in which engineeringchanges and repairs to high density substrates can beachieved without the need for lithography.Inventors: Syamal Kumar Lahiri, Harvey PhillipsDate granted: 29 Oct 04Country granted: Singapore

Method of forming selective electrolessplating on polymer surfacesThis invention provides a method for plating polymersurfaces to the metallisation of printed circuit boardsand flexible substrates.Inventors: William Chen, Peter Moran, Harvey PhillipsDate granted: 29 Oct 04Country granted: Singapore

Vibratory in-plane tunnelling gyroscopeThis invention relates to a gyroscope comprising: aproof mass; a frame supporting the proof mass; aconnection arrangement connecting the proof massand the frame, the connection arrangement having afirst stiffness in a first direction and a second stiffnessin a second direction substantially perpendicular tothe first direction, one of the stiffness beingsignificantly greater than the other stiffness; and apair of elements adapted to sense relative motionthere between in either the first or the seconddirection.Inventors: William Chen, Francis Tay, Xu Yuan, Chua BeeLee, Holden LiDate granted: 29 Oct 04Country granted: Singapore

Procedure for encapsulation of electronicdevicesAn encapsulation procedure for an organic lightemitting diode (OLED) device, especially for thin andtherefore flexible substrates, is disclosed. The device issealed hermatically against environmental andmechanical damage. The procedure includes the useof a thin cover lid holder and a substrate holder thatare designed to handle thin substrates withoutdamaging them.Inventors: Chua Soo Jin, Mark Auch, Ewald GuentherDate granted: 12 Oct 04Country granted: US

Injectable drug delivery systems withcyclodextrin-polymer based hydrogelsThis invention provides injectable controlled releaseddrug delivery formulations which include cyclodextrin,a polymer capable for forming hydrogel withcyclodextrin, a secondary polymer capable ofcomplexing and/or conjugating the drug and alteringthe properties of the hydrogel and a drug in apharmaceutically acceptable injectable aqueous fluid.Inventors: Li Jun, Hanry Yu, Kam LeongDate granted: 30 Sep 04Country granted: Singapore

Support for bending test of flexiblesubstratesA support for facilitating the bending test of flexiblesubstrates is disclosed. Adhesive plastic is applied onthe substrate to keep the shards together afterbreakage, thereby eliminating the process ofcollecting the shards and fitting them back together forfailure analysis.Inventors: Mark Auch, Ewald Guenther, Chua Soo Jin,Chen ZhongDate granted: 17 Aug 04Country granted: US

Patents GrantedPatents Granted


10 IMRE

Conventional MicroElectroMechanical Systems(MEMS) are based on silicon or polymer materialsusing the standard IC processing techniques and inthe last decade or so these have found applications inareas such as micro-fluidics, accelerometers,gyroscopes, etc. The inherent limitation of siliconmaterial in not being able to emit light has motivatedus to consider MEMS made of III-V materials tointegrate light-emitting/detecting devices for noveltunable and coupling applications. MEMS based oncompound semiconductors such as InP and GaAs aregaining increasing relevance for tunable photonicdevices such as those used in Wavelength DivisionMultiplexing (WDM) systems. The key advantage liesin the ability to integrate heteroepitaxial quantumdevices with micromechanical elements. With this aim,our group is working to monolithically integrate amicromachined tunable Fabry-Perot filter based on InPwith a p-i-n photodiode for WDM applicationsaround 1.55 µm. The emphasis is also onreconfigurable OADMs (Optical Add DropMultiplexers) based on novel fabrication approaches.

The core objective of combining novel movablestructures based on MEMS, with InP based photonicdevices, for tuning and coupling applications,encompasses work in three areas. The first one relatesto the optimisation of the fabrication process.Heterostructures of suitable composition and thicknesswere grown. For structural layer (InP), dry etching hasbeen found to be suitable while for releasing thestructures wet etching technique is used. While dryetching has been optimised to obtain nearly verticalside walls on InP structures, wet etching on the otherhand has been optimised with respect to temperature,etch-rate and etch-selectivity. Since release ofmicrostructures is the last step in their fabrication, the

wet etchant has been chosen such that it does notaffect other components such as bond-pads, structurallayer, dielectric sidewalls of platform etc. In OpticalMEMS, the mirror properties, such as reflectivity andstop-band width are very crucial. To meet thesestringent requirements dielectric-type Distributed BraggReflector (DBR) type of mirrors have been used insteadof conventional metallic mirrors. Owing to thesensitivity of mirror optics to the thickness ofconstituent layers, the mirror processing has beenoptimised with feedback from Optical simulations. TheMATLAB code for these optical simulations has beendeveloped within our group. The processed devicecomplete with all components is obtained by sacrificialwet etching and drying of the structures. Evaporationdrying of the microstructures after the wet etching stepposes a problem commonly known as ‘stiction’wherein the forces due to surface tension of the rinsingsolution act on the microstructures. This problem hasbeen sidelined using a technique that has beenperfected in IMRE by processing the structures insubmerged condition and applying specially designedhardware in its operation. The structures are thenreleased by sublimation drying. Figure 1-1 shows areleased and freestanding structure.

The second one relates to the integration of atunable optical filter with Fabry-Perot (F-P) cavity forrealising a tunable photo-detector device. To achievean integrated Photodetector-MEMS device, aPhotodetector and a MEMS-based filter actuator werefabricated in isolation. Preliminary characterisation ofa MEMS-based filter actuator has demonstrated amembrane deflection of > 300 nm with a pull-involtage of 6 volts, as shown in Figure 1-2. Efforts areongoing to successfully integrate these two devices ina monolithic configuration.

Figure 1-1. A freestanding branched beam type microstructure with a DBR Mirror on top of membrane.

IMRE is working to monolithically integrate a micromachined tunable Fabry-Perot filter basedon InP with a p-i-n photodiode for WDM applications around 1.55 mm for use in fibre opticcommunications as well as NIR spectroscopy of gases for detection and blood glucosemonitoring.

Optical Tuning and Coupling in InP-based Photonic DevicesBy Dr Ramam AkkipeddiTeam members: MA Shah, V Shanmugan, J Arokiaraj, Y Cao, SJ Chua, JR Dong, SL Teo and G ChowdhuryCollaborators: A/Prof Francis Tay (NUS) and Mr Andojo Ong (NUS)

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Figure 1-2. Dynamic measurements on InP based ES actuator. Thetotal displacement is > 300 nm on the InP membrane. The change incolour of the membrane indicates the relative movement from theidle state.

The third area is towards achieving a reconfigurableOptical Add-Drop multiplexer (OADM) device. Coupling ofoptical field with wave-guides and optical devices is achallenging issue and the physical separation is a keyparameter for optimising the evanescent fields. Two newarchitectures have been proposed to realise the function. Inone, the concept of Add/Drop is introduced by combiningvertical and Y-branch coupling of optical signals and is

realised by wafer bonding. In another approach, the verticalcoupling is limited to a small section of the epilayer stack andthe waveguide ports are, separated by a simple sacrificiallayer etching technique. In addition, the group has acquiredexpertise in simulation techniques such as coupled-fieldelectromechanical simulation of MEMS using ANSYS,simulation of wave propagation in waveguides using Opti-BPM and simulations using MATLAB for cavity-confinedmicro-optics.

Applications for this research include fibre opticcommunications employing Wavelength Division Multiplexing(WDM) for wavelengths around 1.55 µm, NIR spectroscopyof gases for detection and blood glucose monitoring.

Dr Akkipeddi Ramam has been in the field ofsemiconductors for the last 20 years. He startedhis career with the Defence R & D labs in Indiaworking on GaAs based millimeter wave (mmW)devices and Monolithic Microwave IntegratedCircuits (MMICs). He is currently a DeputyCluster Manager (Research) for the Opto andElectronics cluster in IMRE and has beeninvolved in the fabrication of GaN-based blue

LEDs/Lasers for the past 5 years. His interests are mainly in thefabrication techniques of III-V based opto-electronic devices.Presently, he is looking into new approaches for combining InP-based photonic devices with micromachining concepts.

Semiconductor quantum dots (QDs) are zero-dimensionnanostructures behaving rather similar to atoms with discreteelectronic energy and density of states. These are superiorstructures from which laser diodes are fabricated because oftheir unique properties such as 3-dimensional carrierconfinement and discrete energy states. Potentialimprovements in laser properties using QDs as recombinationmedia include low wavelength chirping effect and lowthreshold current density. Our research team has developedthe capability to fabricate InAs QDs on GaAs substrates

emitting at the 1.3µm telecommunication window using amolecular-beam epitaxy (MBE) technique.

A typical atomic force microscopy (AFM) image of anInAs QDs uncapped layer grown by MBE is shown in Figure2-1(a). High dot density of up to 2x1011 cm-2 can beobtained. We have successfully fabricated four types of InAsself-assembled QD structure emitting at the 1.3 µmtelecommunication window on (100) GaAs substrates usingMBE, i.e., dot-in-a-square well, dot-in-a-triangular well,dot-in-a-parabolic well and dot-in-a-GaAs matrix

structures. The photoluminescence (PL) spectrameasured from these structures were depictedin Figure 2-1(b). All these QD structures areexpected to give different unique propertieswhen fabricated into laser diodes. The dot-in-a-square well configuration ensures groundstate lasing at 1.3 µm from the QDs. Thetriangular or parabolic well can potentiallyease the quantum-confined Stark effect whenunder bias as in the case of a square well.Structures with InAs QDs embedded directly ina GaAs matrix can suppress well-likebehaviour and is expected to give bettertemperature insensitivity threshold currentdensity.

InAs Self-assembled Quantum Dots forPhotonic Devices

IMRE has developed the capability to fabricate InAs Quantum Dots on GaAs substrates emitting at the1.3µm telecommunication window using a molecular-beam epitaxy (MBE) technique.

By Dr Chia Ching KeanTeam members: CK Chia, SJ Chua, JR Dong, ZL Miao, JH Teng, S Tripathy, BC Foo and SL Teo

Figure 2-1. (a) 1 µm x 1 µm AFM image of a typical InAs QD structure grown on GaAsby MBE. The sample was grown at 520oC and has a high dot density of 2x1011 cm-2. (b)Room temperature PL spectra of the as-grown InAs QDs embedded in a In0.12Ga0.88Assquare well, a InxGa1-xAs (x = 0 to 0.4) triangular well, a InxGa1-xAs (x = 0 to 0.4)parabolic well, and a GaAs matrix. All structures are emitting at the 1.3µm telecomwindow at room temperature.

(a)

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In recent years, much research interestin quantum dot (QD) nanostructures havebeen generated by the prospect ofachieving monolithic integration ofphotonic devices based on QDs. Post-growth intermixing is one of the effectiveways to engineer the bandgaps of thesemiconductor quantum well (QW) andQD structures, allowing active-passivecomponents to be monolithically integrated.Various intermixing techniques such asimpurity free vacancy disordering, impurity-induced disordering, plasma-assistedinduced disordering and laser-inducedintermixing have been widely utilised forQW and QD intermixing.

We have demonstrated the tuning of the QD bandgapenergy due to group-V elements exchange in 1.55 µm InAs/InP QDs grown by metal-organic chemical vapour deposition(MOCVD), by rapid thermal annealing (RTA) and laserannealing techniques. In all cases, substantial energy shiftwas observed as shown in Figure 3-1(a) for RTA, and inFigure 3-1(b) for laser-induced intermixing. Typically, amaximum blueshift of about 200 nm can be obtained in QWstructures after intermixing. However, our team hasdemonstrated that a blueshift of more than 500 nm can beobtained in the QD structures.

A large blueshift is preferred in the passive region (forexample in passive waveguides) for monolithic integration ofphotonic devices so that light emission from the activedevices such as lasers will not be absorbed in the waveguideregion. A waveguide in photonic circuits is analogous to awire in electronic circuits. One of the distinguishabledifferences between the intermixed QW and QD structures is

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© 2005 Perspectives is published by the Institute of Materials Research and Engineering (IMRE). Reproduction of material in this publicationwithout written permission from IMRE is prohibited.

Contributors to this issueDr Raman Akkipeddi, Dr Chia Ching Kean, Ms Lee Chun Theng,Mr Eugene Low

Institute of Materials Research and Engineering3 Research Link, Republic of Singapore 117602Tel: (65) 6874 8111 Fax: (65) 6872 0785Email: [email protected] Website: www.imre.a-star.edu.sg

We have demonstrated the tuning of the QD bandgap energy due to group-V elements exchange in 1.55 µmInAs/InP QDs grown by metal-organic chemical vapour deposition (MOCVD), by rapid thermal annealing(RTA) and laser annealing techniques.

Quantum Dot Intermixing for Monolithic Photonic IntegrationBy Dr Chia Ching KeanTeam members: CK Chia, SJ Chua, JH Teng, JR Dong, S Tripathy, BZ Wang, BC Foo and SL Teo

that the PL intensity increased for intermixed QD structures,whereas for QW structures the PL intensity tends to reduceafter intermixing, implying a degradation of the QW materialquality after intermixing.

Our investigation suggests that intermixing is morepronounced in QDs as compared to QWs. Application ofmonolithic photonic integrated QD-based photonic devicesin the next generation high speed optical communicationnetwork is feasible through post-growth intermixing such asimpurity free vacancy disordering and laser annealingtechniques.

Dr Chia Ching Kean received his PhD fromthe University of Sheffield, UK. He is currentlya Research Scientist in IMRE and an AdjunctAssistant Prof with the National University ofSingapore. His research interests include lowdimensional photonic devices and monolithicphotonic integration.

Figure 3-1. (a) Room temperature PL spectra for InAs/InP QD samples capped with 500nmSiO2 before and after annealing. The annealing duration for each temperature was 30s. (b)Room temperature PL intensity as a function of wavelength InAs/InP QD samples underdifferent laser annealing conditions.

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For enquiries about IMRE’s events, please write in to [email protected]

Upcoming Seminars / Workshops / SymposiaDate Event Location Remarks28 Feb - 2 Mar 05 University of New South Wales - Singapore IMRE Seminar Room 1 By Invitation

Research Workshop

17 Mar 05 ON-Singapore Reception IMRE Seminar Room 1 By Registration

26 Apr 05 MSC Chemical Analysis Workshop IMRE Seminar Room 1 By Registration

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