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

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 10(6) at +/- 5 V. From the analysis of I-V-T measurements, a conduction band offset of similar to 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 mu m, while an activation energy was derived as 0.462 +/- 0.073 V and was attributed to the traps.