Molecular-Beam Epitaxial Growth of ZnMgCdS Layers and Their Application to UV-A Photodetectors

Abstract

Zincblende ZnMgCdS quaternary alloy layers were grown by molecular-beam epitaxy. The ZnMgCdS alloy lattice matched with GaAs and exhibited the band-gap energy of approximately 3 eV. Zn, Mg, and CdS were used as source materials. Cd was replaced by Zn or Mg, and the alloy composition was controlled when the growth temperature was set to approximately 210°C. Low-temperature photoluminescence showed dominant band-edge features indicating the high quality of the epilayer. The epilayer was applied to the metal-semiconductor-metal photodetector, and visible-blind UV sensing characteristics were observed.