Realization of W–MgZnO epitaxial growth on BeO-buffered ZnO for UV-B photodetectors

Publication date: 15 October 2013
Source:Journal of Crystal Growth, Volume 381
Author(s): H.L. Liang , Z.X. Mei , Y.N. Hou , S. Liang , Z.L. Liu , Y.P. Liu , J.Q. Li , X.L. Du
A single-phase wurtzite MgZnO film with an optical band gap of 294.5nm was synthesized on ZnO substrate by molecular beam epitaxy, and a photodetector was fabricated working in the ultraviolet-B spectrum region. Wurtzite BeO was adopted to restrain the substrate response as an insulating layer and provide an excellent epitaxial template for high-Mg-content MgZnO growth. In situ reflection high-energy electron diffraction observations, ex situ X-ray diffraction and reflectance spectrum indicate the achievement of high-quality single-phase wurtzite MgZnO with smooth surface and deep ultraviolet band gap. The BeO layer efficiently suppresses the photoresponse from the substrate, as the photodetector demonstrates a sharp cutoff at 290nm, consistent with the optical band gap.