High spectral selectivity metal-semiconductor-metal photodetector

The results of experimental study of the metal-semiconductor-metal (MSM) photodiode based on ZnCdSe/ZnSSe/GaAs heterobarrier structure are presented. MSM-diode with 2.8 mu m Ni-Au interdigitated Schottky barrier contacts, gaps between them of 3 mu m, and total detector area of 100 x 100 mu m(2) have been fabricated and investigated. At a wavelength of 460 nm MSM-diode provides a high spectral selectivity with FWHM of spectral response 4.3 nm, high current sensitivity of 2.27 A/W and low dark current of 200 pA at 30 V bias. The spectral response of the MSM-detector was characterized under various bias conditions. A reduced Schottky barrier height model was adopted to explain the gain mechanism of the MSM-detector under illumination.