ELECTROREFLECTANCE STUDY OF ELECTRONIC STRUCTURE IN a-Si : H

A series of electroreflectance (ER) study has been made on various parametric system of a-Si : H. A drastical change in the ER signal with the film preparation conditions has been found. High power deposition changes the ER spectra from a single broad peak to a crystalline-like ER feature. While, the ER spectrum sharpened gradualy with increasing substrate temperature. These trend can be interpreted by assuming an existence of very small pure silicon crystallites surrounded by hydrogen rich region in a-Si : H. Based upon the experimental data, we discuss the optical transition process and related electronic states near the fundamental edge in conjunction with the correspoding change of optical absorption spectra