Photoresponse of n-ZnO/p-SiC heterojunction diodes grown by plasma-assisted molecular-beam epitaxy

摘要

High quality n-ZnO films on commercial p-type 6H-SiC substrates have been grown by plasma-assisted molecular-beam epitaxy, and n-ZaO/p-SiC heterojunction mesa structures have been fabricated. Current-voltage characteristics of the structures had a very good rectifying diode-like behavior with a leakage current less than 2 X 10~(-4) A/cm~2 at -10 V, a breakdown voltage greater than 20 V, a forward turn on voltage of ~5 V, and a forward current of ～2 A/cm~2 at 8 V. Photosensitivity of the diodes was studied at room temperature and a photoresponsivity of as high as 0.045 A/W at -7.5 V reverse bias was observed for photon energies higher than 3.0 eV.