Electrically tunable spectral responsivity in metal-semiconductor-metal photodetectors based on low-dimensional ZnCdS/ZnMgS/GaP, ZnCdS/ZnS/GaP heterostructures

We report on growth, fabrication and characterization of metal-semiconductor-metal (MSM) photodetectors based on periodic heterostructures with ZnCdS quantum wells separated by ZnMgS and ZnS barrier layers. Heterostructures were grown on semi-insulating GaP substrates by MOVPE. MSM-diodes with width of Ni-Au interdigitated Schottky barrier contacts and gap between them of 3 mu m and total detector area of 100 x 100 mu m(2) have been fabricated. Detecting properties of MSM-heterophotodiodes have been investigated. We observe electrically tunable spectral response of these detectors. At low bias detectors provide narrowband response (FWHM = 18 nm at the wavelength 350 nm) determined by a composition of ZnCdS quantum well. Increasing bias up to 70 V shifts maximum detector sensitivity at the wavelength 450 nm while narrowband response at 350 nm remains. Thus, a two-color detection of light emission is provided. (C) 2015 Elsevier Ltd. All rights reserved.