We investigate different methods of passivating sidewalls of wet etched InAs heterostructures in order to suppress inherent edge conduction that is presumed to occur due to band bending at the surface leading to charge carrier accumulation. Passivation techniques including sulfur, positively charged compensation dopants and plasma enhanced chemical vapor deposition of SiNx do not show an improvement. Surprisingly, atomic layer deposition of Al2O3 leads to an increase in edge resistivity of more than an order of magnitude. While the mechanism behind this change is not fully understood, possible reasons are suggested.
@article{arxiv.1706.01704,
title = {Passivation of Edge States in Etched InAs Sidewalls},
author = {Christopher Mittag and Matija Karalic and Susanne Müller and Thomas Tschirky and Werner Wegscheider and Olga Nazarenko and Maksym V. Kovalenko and Thomas Ihn and Klaus Ensslin},
journal= {arXiv preprint arXiv:1706.01704},
year = {2017}
}