We investigate the optoelectronic properties of single indium arsenide nanowires, which are grown vertically on p-doped silicon substrates. We apply a scanning photocurrent microscopy to study the optoelectronic properties of the single heterojunctions. The measured photocurrent characteristics are consistent with an excess charge carrier transport through mid-gap trap states, which form at the Si/InAs heterojunctions. Namely, the trap states add an additional transport path across a heterojunction, and the charge of the defects changes the band bending at the junction. The bending gives rise to a photovoltaic effect at a small bias voltage. In addition, we observe a photoconductance effect within the InAs nanowires at large biases.
@article{arxiv.1510.01143,
title = {Photocurrents in a Single InAs Nanowire/ Silicon Heterojunction},
author = {Andreas Brenneis and Jan Overbeck and Julian Treu and Simon Hertenberger and Stefanie Morkötter and Markus Döblinger and Jonathan J. Finley and Gerhard Abstreiter and Gregor Koblmüller and Alexander W. Holleitner},
journal= {arXiv preprint arXiv:1510.01143},
year = {2015}
}