Multicolour photodetector based on a ZnSe/ZnTe/GaAs heterostructure

Structural, optical, and photoelectric properties of a ZeSe/ZnTe/GaAs heterostructure and a metal – semiconductor – metal detector (MSM-detector) based on this heterostructure are investigated. The composition and thickness of individual layers of the heterostructure are determined by the methods of energy dispersive analysis and Raman spectroscopy, and the optical properties are studied using the photoluminescence spectra. The ZeSe/ZnTe/GaAs heterostructure MSM-detector is highly sensitive. In particular, at a wavelength of 620 nm, the detector response signal corresponds to an ampere – watt sensitivity of 0.19 A W^-1 and an external quantum efficiency of 38%. The MSM-detector photoresponse demonstrates three peaks located at wavelengths of 510, 620, and 870 nm. For the MSM-diode with a pin contact width of 2.8 μm, distances between them of 2.8 mm, and a total photosensitive area of 100 × 100 mm, the dark current density at room temperature constitutes 10^-8 A cm^-2.