Metal–Semiconductor–Metal–ZnS/GaP Detectors for the UV and Visible Spectrum with Electrically Tunable Spectral Photosensitivity

High-quality ZnS epitaxial layers are grown on GaP semiconductor substrates by the MOCVD method. Photodetectors for the visible and UV parts of the spectrum based on interdigital Schottky metal–semiconductor–metal (MSM) barrier contacts to the ZnS/GaР semiconductor structure have been fabricated and studied. The detectors exhibit low dark currents. The dependence of the characteristics of the spectral response of the detectors on the bias voltage is established. It was found that the long-wavelength response limit of ZnS/GaP MSM detectors can shift from 355 to 450 nm when the bias voltage is changed from 10 to 30 V. At the maximum photosensitivity wavelength of 450 nm, the ampere–watt sensitivity of the detector was 0.3 A/W at a bias voltage of 60 V, and the quantum efficiency is 82%.