Optical-beam profiling by field-controlled metal–semiconductor–metal structures

Abstract

Optical-beam profiling properties of Schottky-barrier metal–semiconductor–metal (MSM) structures have been investigated experimentally. Making use of a planar molybdenum/n-type silicon/molybdenum (Mo/n-Si/Mo) MSM structure with a wide electrode separation, one-dimensional (1-D) profiling of optical-beam intensity distribution from a helium–neon (He–Ne) laser was carried out. It was confirmed that, in addition to the existing photosensing function, the sensitivity (output photocurrent) of such a structure could be controlled by applying a bias via lateral spreading of the surface space-charge-region (SCR) at the side of the reverse-biased Schottky-junction.

Keywords:

• Planar metal–semiconductor–metal structure
• Optical-beam profiling
• Field-controlled optical sensor

Acknowledgements

The authors wish to thank T. Masui of Tokai University for technical assistance and S. Niemcharoen of King Mongkut's Institute of Technology for valuable discussions and comments throughout this work.