Hydrogen exposure effects on anodically etched GaAs nanowires in liquid electrolyte

GaAs nanowires fabricated by an anodic etching have some advantages over conventional dry crystal growth and wet chemical dissolution techniques in terms of their formation. However, undesired electrical insulating behavior caused by deep interface states is observed. It is known that the interface states originate from the dissociated As atoms between GaAs core and Ga2O3 outer layer. Here, we investigated the effect of hydrogen exposure on anodically etched GaAs nanowires in liquid electrolyte in order to reduce the high density of interface states. As a result of different hydrogen exposure time, Raman spectra indicated that the longitudinal optical phonon intensities gradually decreased and slightly upshifted with increasing the electrolysis time. This means that the density of interface states was reduced by the hydrogen exposure. Based on the Raman analysis, we fabricated thin-film transistors (TFTs) using GaAs nanowires with 600 s of reverse electrolysis treatment. The TFT having nanowire random network channel showed good electrical properties (field-effect mobility: 2.3 cm2/Vs). This is comparable to TFTs using random network channel composed of other one dimensional materials.