Electrical and Optical Properties of n-ZnO/p-SiC Heterojunctions

Abstract

A series of n-ZnO/p-6H–SiC heterostructures have been grown by molecular-beam epitaxy, and electrical and optical properties of the mesa diodes have been studied. Current versus voltage (I–V) characteristics of the samples revealed a good rectifying behavior of all samples with a typical leakage current less than 10-7 A at -8, and with forward currents changing from sample to sample and at 8 V lying in the range 0.8–10 mA. Capacitance–voltage (C–V) profiles and double pulse deep level transient spectroscopy (DDLTS) indicate interface states in the 1012–1013/cm2 eV range, sharply peaked below 0.5 eV. Under forward bias electroluminescence (EL) emission was observed from most of the samples in yellow and violet regions with maxima at ∼2.1 and ∼2.92 eV, which attributed to the SiC side of the n-ZnO/p-6H–SiC heterojunction, from the comparison with the photoluminescence spectra of n-ZnO and p-SiC.