Enhanced ultraviolet GaN photo-detector response on Si(111) via engineered oxide buffers with embedded Y_2O_3/Si distributed Bragg reflectors

摘要

Based on a virtual GaN substrate approach on Si(111) by a step graded double oxide (So_2O_3/Y_2O_3) buffer, we report a "proof of principle" study on the enhanced photo-response of ultraviolet GaN photo-detectors due to embedded DBRs (distributed Bragg reflectors). Embedded DBRs benefit from an order of magnitude lower number of superlattice sequences in contrast to 111- nitride systems due to the high refractive index contrast between high-k Y_2O$3 and low-k Si. The UV (ultraviolet) reflectance efficiency of the designed DBR is proven by a considerable photo-response increase in the U V range in comparison to reference GaN layers on Si(111) without DBRs.