Ultraviolet polarized light emitting and detecting dual-functioning device based on nonpolar n-ZnO/i-ZnO/p-AlGaN heterojunction

We report on demonstration of 386 nm light emission and detection dual-functioning device based on nonpolar a-plane n-ZnO/i-ZnO/p-Al0.1Ga0.9N heterojunction under both forward and reverse bias. The electroluminescence (EL) intensity under reverse bias is significantly stronger than that under forward bias, facilitated by carrier tunneling when the valence band of p-AlGaN aligns with the conduction band of i-ZnO under reverse bias. Also amid reverse bias, the photodetection responsivity is 0.108 A/W, much larger than that of the reported n-ZnO/p-GaN detectors. Optical polarization of the light emission is studied for potential polarization-sensitive device applications. The demonstration of the proposed device provides an important pathway for the multifunctional devices operating in UV spectrum.