Fabrication and Characterization of Nickel Amorphous Silicon Metal-Semiconductor-Metal Photoconductors

Fabrication and electrical characterization of metal-semiconductor-metal (MSM) photodetectors using nickel and amorphous silicon is reported. Fabricated detectors exhibit dark currents in the order of 10^-12 A, a dynamic range higher than 10⁶, and responsivity of 0.12 A/W. Detector current changes linearly with applied bias voltage in the range of 0 to 30 V, and incident optical power density between 0 and 107 mW/cm². It was found that with channel length of less than 25 mum, external quantum efficiency of more than 30% is achievable. Such detectors are particularly suitable for imaging applications with very large area pixels.