Amorphous silicon-based unipolar detector for color recognition

The device performance of a novel color sensitive diode (p-i-i-i-n-diode)-based on amorphous silicon is discussed. The detectors are developed with regard to the /spl mu//spl tau/-(carrier mobility/spl times/lifetime)-product and the bandgap of the different i-layers resulting in a voltage controlled spectral response. Since the linear independence of the spectral response curves and a linear response of the photocurrent on the incident light intensity is a prerequisite for the generation of a red-green-blue signal, the influence of light intensity on the color separation is examined by spectral response measurements under different monochromatic bias illumination. Additionally, numerical simulations are carried out to study the optoelectronic properties of these devices. Finally, a deconvolution method is presented which allows the transformation of the measured spectral response curves into a red-green-blue signal.