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.