Asymmetric Current Flow in a Native Oxide/Indium Selenide Heterostructure

This paper examines for the first time the current-voltage behavior of native oxide/InSe heterostructures with the native oxide grown at room temperature on a cleaved (0001) InSe surface and analyzes the processes that determine the shape of their current-voltage curves. The native oxide is shown to be an insulator with an electric conductivity of ∼10–11 S/cm and a relative static dielectric permittivity of 10.37 at room temperature. Low bias voltages lead to monopolar carrier injection into the oxide layer. At sufficiently high bias voltages, thermal field trap ionization (Poole-Frenkel effect) and thermionic emission occur. The asymmetry of the current-voltage behavior of native oxide/InSe heterostructures may be due to different trap concentrations and the difference in the trap energy distribution between the near-surface region of the oxide film and the native oxide/semiconductor substrate interface.