| In the past several years, research on wide band gap semiconductors has led to major advances which make these materials viable in many technological applications including blue-green light emitting diodes and lasers, electron emission display devices, high temperature (T) electronics, and optical and tribological coatings. In all of these applications, materials characterization is very important. For example, in the short wavelength optical emission applications of II-VI semiconductors, non-destructive methods for determining layer thickness and composition are of great interest. In the electron emission and high-T electronic applications of amorphous carbon (a-C) and diamond thin films, respectively, non-destructive methods for estimating the sp{dollar}sp2{dollar} C content are needed. Finally, in the diamond film growth process, the structural and optical properties of the films are found to evolve with thickness. Thus, real time measurements are needed in order to follow the growth process, and to provide insight into optimization of nucleation and coalescence. In this thesis, spectroscopic ellipsometry in various data collection modes has been applied to attack such problems in wide band gap semiconductor research. Spectroscopic ellipsometry has advantages over other techniques because it is based on photons in the near-infrared to near-ultraviolet range. Thus, it is non-invasive and non-destructive, and can be readily applied as an in situ, real time probe. |
