STUDIES OF OPTICAL-ABSORPTION COEFFICIENTS-ALPHA OF A-SI-H BY PHOTOLUMINESCENCE ABSORPTION-SPECTROSCOPY

The limit of the film thickness that could be measured by optical absorption coefficients alpha by photoluminescence absorption spectroscopy (PLAS) is studied and found to be about 400 to 500 Angstrom for present experimental conditions. Points at issue to improve the limit to thinner films are discussed by using simulations. Results of preliminary experiments on the effect of the applied electric field to PLAS devices are discussed.