Visible-blind ultraviolet photodetectors based on ZnMgBeSe Schottky barrier diodes

Planar geometry Schottky barrier photodiodes designed for visible-blind ult raviolet detection have been fabricated. They are based on ZnMgBeSe alloys grown by molecular-beam epitaxy. High crystalline quality is achieved, whic h leads to a high responsivity (0.17 A/W at 375 nm) and a sharp cutoff of m ore than three orders of magnitude. As attested by the linear variation of the photocurrent with the optical excitation, there is no internal gain mec hanism. A detectivity of 2x10(10) mHz(1/2) W-1 is obtained showing that low -noise devices with high sensitivity have been fabricated. (C) 2001 America n Institute of Physics.