Abstract
A novel structure of photo sensor is disclosed. The equivalent circuit of the invented photo sensor comprises a photo transistor integrated with a surface photo sensor. The structure of the surface photo sensor is substantially identical to the base-emitter junction of the photo transistor and may be prepared in the same process. The junction depletion region of the surface photo sensor locates adjacent to the light incident surface, whereby decay of incident light is minimal and more electron-hole pairs are generated. The present invention also discloses semiconductor material containing the invented photo sensor assembly of the invented photo sensor and method for preparation of the photo sensor, the semiconductor material and their assemblies.