Image and color sensitive detector based on double p-i-n/p-i-n a-SiC:H photodiode

Abstract

AbstractA two terminal image and color sensitive detector based on two stacked sensing/switching p-i-n a-SiC:H diodes is presented. The imaging is performed in a write-read simultaneous process: the write exposure, which converts the optical image into a localized packet of charges and the readout which performs the charge to current conversion by detecting the photocurrent generated by a light beam scanner. By sampling the absorption region at appropriated voltages it is possible to extract separately the RGB integrated information with a good rejection ratio. Readout of 1000 lines per second is achieved allowing continuous and fast color recognition and image detection. A trade-off between the sensing and the switching diodes thicknesses is established in order to enhance the green recognition. When it is used a thin a-SiC:H, optimized for red transmittance and blue collection, and a switching absorber thick enough to absorb most of the incoming green light,the detector behaves itself as a filter giving information about the wavelength and the position of the optical image.