Current–voltage characteristics and photovoltaic effect of a Au/ZnFe₂O₄/GaN Schottky junction

Abstract

A Au/ZnFe2O4/GaN Schottky junction with a semiconducting heteroepitaxial ZnFe2O4 insertion layer was prepared by using a combined synthesis process of pulsed laser deposition and sputtering. The current–voltage (I–V) and capacitance–voltage (C–V) characteristics of the Schottky junction, as well as its photovoltaic effect, were investigated under dark conditions or ultraviolet (UV) or blue illumination. Insertion of the semiconducting ZnFe2O4 interlayer clearly induced an increase in the rectification ratio. Based on I–V measurements in a forward bias region, the barrier height and ideality factor of the Au/ZnFe2O4/GaN junction were estimated to be about 0.89 eV and 1.58, respectively. On the other hand, C–V measurement in a reversed bias region suggested a relatively larger barrier height of ∼1.32 eV. The Au/ZnFe2O4/GaN junction showed an open-circuit voltage of ∼0.5 V under UV light and a clear switching photocurrent behavior with UV ON/OFF. A schematic band model with two interfaces, Au/ZnFe2O4 and ZnFe2O4/GaN, was proposed to explain the measured barrier heights in forward and reverse bias regions.

Physical Investigations on Bias-Free, Photo-Induced Hall Sensors Based on Pt/GaAs and Pt/Si Schottky Junctions

“…The image potential energy associated with this field is given by the following Equation (1) Figure 1c,d show the physical origin of a Schottky photo-diode according to the theory of image forces [24]. If the metal has a work-function much higher than the semiconductor, a Schottky junction is formed at the interface [25]. Electrons move from the semiconductor to the metal, leaving uncompensated holes in the semiconductor.…”