1. Determination of the Current Voltage Signatures of NanoGUMBOS Kalyan Kanakamedala, Sergio L. de Rooy, Susmita Das, Bilal El-Zahab, Isiah M. Warner, and Theda Daniels-Race Nanoscale Electronic Materials Characterization Group Electronic Materials and Devices Laboratory Department of Electrical & Computer Engineering

2. OUTLINE Motivation Introduction: Ionic Liquids (ILs), Frozen ILs, and NanoGUMBOS Experiment/Results Conclusions Acknowledgements

3. Motivation Electrical characterization of new form of nanomaterial Provide proof of principle for future devices from hybrid electronic materials (HEMs)

4. Introduction Ionic Liquids (ILs) – Organic salts normally with melting points ≤ 100 o C RTIL (room temperature ionic liquids)-liquid at room temp~27 o C Frozen (solid state) ionic liquids- solid above room temperature

5. Ionic Liquids (ILs)-continued – High ionic conductivity – Highly solvating For organic and inorganic compounds For hydrophobic and hydrophilic materials – Recyclable (also known as “green solvents”) – Broadly tunable: solubility, melting point, viscosity

6. Frozen ILs as NanoGUMBOS: A “New” Material GUMBOS: Group of Uniform Materials Based on Organic Salts Rhodamine 6G Tetraphenylborate Frozen ionic liquids: 25 o C < Melting points < 250 o C.

7. NanoGUMBOS Characteristics – First-time synthesis of nanoparticles from ILs in the frozen (solid) state – Maintain tunability: solubility, melting point, viscosity – Designer nanoparticles – Can be functionalized with one or more properties such as Fluorescence Magnetism Chirality Electrical Properties

8. Experiment/Results – First-time examination of electrical characteristics of nanoGUMBOS based nanowires – Current-voltage experiments Phase 1: Determine conductivity (or not) of nanowires Phase 2: Obtain I-V characteristics for R6G TPB

9. PHASE 1: Preliminary measurements were made using a very basic structure made of copper on glass slide. Copper of 0.1μm thick with a channel of width ~100μm Ionic liquid drop casted between two copper plate-like structures

11. PHASE 2: Refinement of measurement structure Inter-digitated structure was built using standard optical lithography. Distance between inter-digitated “fingers” was 10 μm, as the length of the nanowires was expected to be ~20μm.

12. Model Inter-digitated structure Contact pads Inter-digitated fingers Drop casted nanowires suspended in H 2 O

13. Gold inter-digitated structure with 10μm distance between fingers Fig 1. Complete StructureFig 2. Single inter-digitated structure of the same device

14. Low vacuum sample isolation chamber SCS system Vacuum chamber Vacuum pump Nitrogen line Vacuum inside the chamber : 1 - 4 mmHg Nitrogen pressure: 750 mmHg Semiconductor Characterization System (SCS 4200) Vacuum system N2N2 Bell Jar

15. Nanowires dispersed onto the gold inter-digitated structure; observed using an optical microscope Fig 1. Pair of gold electrodes of Inter-digitated structure. Fig 2. Closer look at the same gold electrodes.

16. SEM images of the nanowires Gold structure Bunched Nano-wires

18. Conclusions Observed conductivity in ionic liquid (Rhodamine 6G tetraphenylborate, R6G TPB) nanoGUMBOS based nanowires Fabricated a photolithographically designed sample mount and facile vacuum chamber for IL nanowire electrical measurements Measured I-V characteristics of R6G TPB

19. Acknowledgements Golden Hwuang, Research Associate, Electronic Material and Device Laboratory (EMDL), LSU Department of Electrical & Computer Engineering Naga Korivi, Graduate Assistant, Electronic Material and Device Laboratory (EMDL), LSU Department of Electrical & Computer Engineering The authors gratefully acknowledge the support of the sponsors Louisiana Board of Regents LEQSF(2011-14)-RD-A-07, National Science Foundation (2010)-PFUND-172 and NASA(2011)- DART-44.

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