Rocksalt MgS solar blind ultra-violet detectors

Studies using in-situ Auger electron spectroscopy and reflection high energy electron diffraction, and ex-situ high resolution X-ray diffraction and electron backscatter diffraction reveal that a MgS thin film grown directly on a GaAs (100) substrate by molecular beam epitaxy adopts its most stable phase, the rocksalt structure, with a lattice constant of 5.20 angstrom. A Au/MgS/n(+)-GaAs (100) Schottky-barrier photodiode was fabricated and its room temperature photoresponse was measured to have a sharp fall-off edge at 235 nm with rejection of more than three orders at 400 nm and higher than five orders at 500 nm, promising for various solar-blind UV detection applications. Copyright 2012 Author(s). This article is distributed under a Creative Commons Attribution 3.0 Unported License. [http://dx.doi.org/10.1063/1.3690124]