Charge Transfer Properties Through Graphene Layers

(Production & QA of Graphene Samples)

P. Thuiner1,2, R. Hall-Wilton3, R. B. Jackman4, H. Müller1, T. T. Nguyen4, R. de Oliveira1, E. Oliveri1, D. Pfeiffer1,3, F. Resnati1,

L. Ropelewski1, J. A. Smith4, M. van Stenis1, R. Veenhof5

1CERN, 2Technische Universität Wien, 3ESS, 4University College London, 5Uludağ University

Patrik Thuiner et al. 2GDD Meeting – 2015/02/18

• Goal: create a device fully transparent to electrons and fully opaque to ions

• Graphene is narrowest and thinnest possible conductive mesh with pore size < 1 Å

• Study of charge transfer through graphene layers suspended on Cu meshes or GEM electrodes(hole diameter ≥ 30 µm!)

Patrik Thuiner et al. 3IEEE 2014 NSS/MIC – 2014/11/13

Graphene Transfer

Acetone

Nitric Acid

1. Find “good” side of copper foil2. Etch away “bad” layer in

nitric acid3. Spin-coat with PMMA4. Etch away copper foil with

Fe 3 nitrate5. PMMA with graphene layer on

bottom floating on Fe 3 nitrate6. First step of cleaning with

demineralized water7. Second step of cleaning with

demineralized water8. PMMA with graphene on

bottom scooped out with mesh/GEM

9. PMMA dissolved with acetone in Critical Point Dryer

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Iron 3 Nitrate Iron 3 Nitrate Demineralized Water

Demineralized Water

Demineralized Water

Patrik Thuiner et al. 4GDD Meeting – 2015/02/25

Charge Transfer Measurements

Tnpnp

np

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ADC channels

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ADC channels

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P2P1ED1

Telectron = P1/P2

Pre-AmpPre-Amp

A

Ions

AIons

AElectrons 𝑇 𝑖𝑜𝑛=𝐼 h𝑐𝑎𝑡

𝐼 h𝑐𝑎𝑡 +𝐼 h𝑚𝑒𝑠

Patrik Thuiner et al. 5

• Setup (gas detectors)– Need for conductive support structure– Free-standing graphene membranes of

hole diameter ≥ 30 µm – Beam size: order of mm²

• Production/Transfer– Contamination– Layer integrity

• Qualitiy assurance– Contaminations: SEM– Homogeneity, defects: Raman spectroscopy

GDD Meeting – 2015/02/25

Challenges

D peak2D peak

G peak

Patrik Thuiner et al. 6GDD Meeting – 2015/02/25

Backup

Patrik Thuiner et al. 7GDD Meeting – 2015/02/25

Preliminary results

Patrik Thuiner et al. 8GDD Meeting – 2015/02/25

SEM

Patrik Thuiner et al. 9IEEE 2014 NSS/MIC – 2014/11/13

Patrik Thuiner et al. 10IEEE 2014 NSS/MIC – 2014/11/13

Mesh Production

Nitric Acid

120°C

1. Find “good” side2. Etch away “bad” layer in

¼ nitric acid 68% for 4 min3. Spin-coat with HIPR6512

photoresist and cure for one hour at 120°C

4. Flip good side to bottom5. Laminate top side with

FX930 photoresist6. Put hole mask onto

photoresist7. Irradiate with UV light8. Develop negative

photoresist (removed at hole positions)

9. Apply ferric perchloride to top side

UV light Ferric Perchloride

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Patrik Thuiner et al. 11IEEE 2014 NSS/MIC – 2014/11/13

Mesh Production

Ethanol

Acetone

1. Ship samples to UCL2. Dissolve FX930

photoresist in Ethanol

3. HIPR6512 photoresist still protects graphene layer

4. Dissolve HIPR6512 photoresist with acetone in Critical Point Dryer

5. Graphene membrane on copper mesh

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