1. Charge Transfer Properties Through Graphene Layers (Production & QA of Graphene Samples) P. Thuiner 1,2, R. Hall-Wilton 3, R. B. Jackman 4, H. Müller 1, T. T. Nguyen 4, R. de Oliveira 1, E. Oliveri 1, D. Pfeiffer 1,3, F. Resnati 1, L. Ropelewski 1, J. A. Smith 4, M. van Stenis 1, R. Veenhof 5 1 CERN, 2 Technische Universität Wien, 3 ESS, 4 University College London, 5 Uludağ University

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

3. IEEE 2014 NSS/MIC – 2014/11/13Patrik Thuiner et al.3 Graphene Transfer Acetone Nitric Acid 1.Find “good” side of copper foil 2.Etch away “bad” layer in nitric acid 3.Spin-coat with PMMA 4.Etch away copper foil with Fe 3 nitrate 5.PMMA with graphene layer on bottom floating on Fe 3 nitrate 6.First step of cleaning with demineralized water 7.Second step of cleaning with demineralized water 8.PMMA with graphene on bottom scooped out with mesh/GEM 9.PMMA dissolved with acetone in Critical Point Dryer 123 456 7 ? 89 Iron 3 Nitrate Demineralized Water

4. GDD Meeting – 2015/02/25Patrik Thuiner et al.4 Charge Transfer Measurements TnpTnp npnp npnp P2P2 P1P1 E D1 T electron = P 1 /P 2 Pre-Amp A Ions A A Electrons

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 – 2015/02/25Patrik Thuiner et al.5 Challenges D peak 2D peak G peak

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

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

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

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

10. IEEE 2014 NSS/MIC – 2014/11/13Patrik Thuiner et al.10 Mesh Production Nitric Acid 120°C 1.Find “good” side 2.Etch away “bad” layer in ¼ nitric acid 68% for 4 min 3.Spin-coat with HIPR6512 photoresist and cure for one hour at 120°C 4.Flip good side to bottom 5.Laminate top side with FX930 photoresist 6.Put hole mask onto photoresist 7.Irradiate with UV light 8.Develop negative photoresist (removed at hole positions) 9.Apply ferric perchloride to top side UV light Ferric Perchloride 123 456 7 ? 89

11. IEEE 2014 NSS/MIC – 2014/11/13Patrik Thuiner et al.11 Mesh Production Ethanol Acetone 1.Ship samples to UCL 2.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 123 45