OPTICAL STUDIES OF UNDOPED AND DOPED WIDE BANDGAP CARBIDE AND NITRIDESEMICONDUCTORS

The wide bandgap semiconductors Silicon carbide and gallium nitride ha ve been studied by Raman scattering, photoluminescence, and infrared a bsorption. Raman scattering studies determined crystalline quality and polytype of bulk and thin film samples at room temperature. Photolumi nescence studies were carried out as a function of temperature to dete ct and/or identify impurity centers and structure related defects and their role on the electronic properties of the materials. Infrared abs orption spectroscopy was used to measure the binding energy of donors and their concentration.