Narrow spectral response schottky photodiodes.

Spicer's absorption diffusion model is extended to analyze Schottky photodiodes which possess special characteristics. The model describes the generation of minority carriers by optical absorption in the bulk of a semiconductor material. The magnitude and shape of the spectral response for a minimally depleted device is found to depend on the rate of variation of the absorption coefficient with wavelength on the thickness of the absorbing region T and on the minority carrier's diffusion length l. Narrow spectral response can exist in this device only in the wavelength region wherein the absorption coefficient alpha is rapidly changing. A combination of high quantum efficiency with sharp tuning is found to exist.