Metal–insulator–semiconductor Schottky barrier structures fabricated using interfacial BN layers grown on GaN and SiC for optoelectronic device applications

Abstract

Metal–insulator–semiconductor Schottky barrier structures on GaN and 6H-SiC using highly stable interfacial BN layers have been investigated. As reported earlier, such structures fabricated with Ti contacts are capable of withstanding up to 350 and 600 °C when based on 6H-SiC and GaN, respectively. In this work we fabricated diode structures using interfacial BN layers and optically transparent Au contacts. Visible–blind photosensitive structures on GaN and 6H-SiC and prebreakdown light-emitting diode (LED) structures on 6H-SiC have been characterized. The radiant and spectral sensitivities of the photosensitive structures were measured in the range of 200–400 nm. The potential barrier heights determined from photoresponse measurements were 2.7 and 2.88 eV for GaN- and SiC-based samples, respectively. The spectrum of 6H-SiC and p-GaN-based prebreakdown LED structures measured through transparent Au electrodes extended to the ultraviolet region. The optical emission power of the 6H-SiC-based LED structures measured in the range 200–1100 nm saturated to about 10−8 W at current densities close to 200 A/cm2. Prospects for applications of the diode structures described in advanced visible–blind optoelectronic sensors are discussed.