Speaker
Description
Compound semiconductor nanowires are a promising solution for nanoscale optoelectronic devices such as lasers, LEDs, solar cells and photodetectors because of their high aspect ratio, large surface-to-volume ratio and carrier/photon confinement in two dimensions. In this work, we investigate the use of transparent conducting oxides (TCOs) to make a radial heterojunction InP nanowire array. TCOs can act both as a carrier injection layer and a passivation layer.
Patterned vertical InP nanowire arrays were grown by selective area epitaxy, in which a dielectric mask was used to predefine the size and position of the nanowires. This technique can produce InP nanowires that are defect-free with high optical quality and the ability to precisely control dopant incorporation. The behaviour of different n-type TCOs like ZnO and SnO2-x are investigated on p-InP. TCOs were deposited conformally on the different p-type InP nanowire samples to make a p-n junction followed by top and bottom metal contacts. Current vs voltage (I-V) and electroluminescence measurements were performed to characterise the devices. I-V measurements indicate a typical diode characteristic with a low threshold voltage. Strong electroluminescence was obtained from the nanowires demonstrating LED behaviour without involving complex fabrication processes. Several issues like metal absorption, low doping concentration, series resistance and free carrier absorption are discussed. The TCOs and nanowires growth conditions were optimised to realise low power consumption and highly efficient LEDs.
Acknowledgements:
We acknowledge The Australian Research Council for financial support and The Australian National Fabrication Facility, ACT Node for access to the growth and fabrication facilities used in this work.
| Speaker Country | Australia |
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