| In this thesis, we study the electronic and optical properties of hydrogenated amorphous silicon, hydrogenated amorphous silicon being the most prevalent amorphous semiconductor in use in large area microelectronic products today. We start with a thorough analysis of the density of states functions associated with this material. In particular, we clearly identify where these functions exhibit a square-root functional form and where there are deviations from such a form. We also study the nature of the deviations that occur. Then, we develop an empirical model for the conduction band and valence band density of states functions, which captures the basic features exhibited by these experimental results. A modified empirical model, which more accurately captures the experimental results, is then suggested, and a comparison with experiment is presented.; Then we study how the optical properties of amorphous semiconductors are related to these density of states functions. In doing so, we introduce the joint density of states function, which provides a measure of the number of optical transitions allowed between the electronic states associated with the valence band and those associated with the conduction band. (Abstract shortened by UMI.)... |
