MSM-photodetector with ZnSe/ZnS/GaAs Bragg reflector

The effect of a ZnSe/ZnS/GaAs distributed Bragg reflector on the spectral response of a metal–semiconductor–metal (MSM)-diode is investigated. Good agreement is obtained between the calculated and experimental reflection spectra of the ZnSe/ZnS/GaAs heterostructure forming a distributed Bragg reflector in the MSM-diode. The MSM-detector provides a two-color response at 420 and 472 nm, a sharp decrease in photosensitivity in the long-wave part of the response signal, high quantum efficiency of 53%, and low dark current of 5 × 10 −10 A. The two-color response of the detector can be adjusted to the desired wavelength by appropriately selecting the heterostructure parameters.