Studying surface Fermi level pinning in GaP nanowires with gradient Kelvin probe microscopy

Abstract

In this work, we use scanning Kelvin probe gradient force microscopy to study surface Fermi level pinning in horizontal undoped nanowires with axial GaP/GaPAs heterojunction. The nanowires were separated from the growth substrate and dispersed on smooth surface of Ni/Si substrate. Then longitudinal and transverse surface potential profiles of several nanowires were captured. The study revealed a distinction between the work function of GaP and GaPAs regions. It was shown that the Fermi level in undoped GaP nanowires was pinned in the middle of the energy gap.