Microcrystalline silicon thin films for optical applications

Microcrystalline hydrogenated silicon thin films, deposited by the cyclic C VD method, were used for the production of bidimensional detectors. The opt ical detectors use a standard TCO/mu c-p-i-n Si:H configuration as active d evice and two lateral ohmic contacts. Based on the lateral photovoltaic eff ect developed in the p-i-n structure under local illumination, we propose t o develop a new sensing method for the recognition of a light pattern proje cted onto a p-i-n optical sensor. It was used strong spatially fixed light spots to simulate an image and a weak chopped light scanning-beam to make i ts recognition. The induced ac component of the lateral photovoltage was fo und to be dependent on the image position and intensity. A small signal cir cuit analysis and simulation is presented. Applications for image detection are discussed. (C) 1998 Elsevier Science Ltd. All rights reserved.