| AVS 58th Annual International Symposium and Exhibition | |
| Electron Transport in Low Dimensional Materials Focus Topic | Tuesday Sessions |
| Session ET+EM+NS+GR-TuM |
| Session: | Electron Behaviors in Nanoelectronics, Interconnect, and Carbon-based Materials |
| Presenter: | Chao Liu, Simon Fraser University, Canada |
| Authors: | C. Liu, Simon Fraser University, Canada O. Einabad, Simon Fraser University, Canada S. Watkins, Simon Fraser University, Canada K.L. Kavanagh, Simon Fraser University, Canada |
| Correspondent: | Click to Email |
Copper (Cu) electrical contacts to as-grown gallium arsenide (GaAs) nanowires have been fabricated via electrodeposition. The nanowires are zincblende (111) oriented grown epitaxially on n-type Si-doped GaAs(111)B
substrates by gold-catalyzed Vapor Liquid Solid (VLS) growth in a metal organic vapour phase epitaxy (MOVPE) reactor. The epitaxial electrodeposition process, based on previous work with bulk GaAs substrates, consists of a substrate oxide pre-etch in dilute ammonium hydroxide carried out prior to galvanostatic electrodeposition in a pure Cu or Fe sulphate aqueous electrolyte at 20C. The conductivity of wires was controlled via the addition of carbon tetrabromide (CBr4) during growth. For nominally undoped GaAs nanowires, we find that Cu or Fe has a preference for growth on the gold catalyst avoiding the sidewalls. After etching the gold, both metals still preferred to grow only on the tops of the nanowire, consistent with the location of the largest electric field. Core-shell GaAs nanowires with highly conductive carbon-doped shells were fabricated via changing the Ga precursors form triethylgallium to trimethylgallium for radial growth. Increasing the conductivity of the nanowires in this way, not surprisingly; meant that Cu nucleation and growth began to occur on the sidewalls as well as on the gold catalyst. Finite element simulations will be compared to our electrodeposition results towards the calibration of nanowire conductivity.