Properties of isotype n-ZnO/n-GaN heterostructures studied by <i>I</i>–<i>V</i>–<i>T</i> and electron beam induced current methods

Abstract

Electrical properties of isotype n-ZnO/n-GaN heterostructures obtained by radio-frequency sputtering of ZnO films on GaN layers are studied by means of temperature dependent current–voltage (I–V–T) characterization and electron beam induced current (EBIC) measurements. The n-ZnO/n-GaN diodes showed highly rectifying behavior with a forward and reverse current ratio of about 106 at ± 5 V. From the analysis of I–V–T measurements, a conduction band offset of ~0.62 eV was derived. From EBIC measurements, the minority carrier diffusion length of ZnO was estimated to lie in the range 0.125–0.175 µm, while an activation energy was derived as 0.462 ± 0.073 V and was attributed to the traps.