Infrared reflectivity and transport investigations of GaN single crystals and homoepitaxial layers

The aim of this paper is to examine infrared reflectivity as a nondestructi ve characterization for gallium nitride bulk and its homoepitaxial epilayer s. For that purpose, we have compared infrared reflectivity data (electron concentration and optical mobility) with the results of low-field Hall meas urements. We examined various bulk GaN crystals and homoepitaxial layers gr own on highly conducting GaN substrates. In our research, we paid special a ttention to the polarity of the sample surface as it influences the electro nic properties of the homoepitaxial layers.