Photoreflectance and X-ray Diffraction Study of Semiconductor Heterostructuresand Quantum Wells

摘要

The modulation spectroscopy method of photoreflectance and double crystal X-raydiffraction were used for the characterization and development of III-V compound semiconductor heterostructures and quantum wells. The materials studied were based on the compounds of gallium arsenide and indium phosphide grown by molecular beam epitaxy and metalorganic vapor phase epitaxy. The structure of the grown samples were determined from the X-ray diffraction curves using theoretical calculations based on the dynamical theory of X-ray diffraction. A new procedure was developed for the determination of the period of multiple quantum well structures grown on misoriented substrates. Peculiar below-bandgap features in photoreflectance, such as interference in epitaxial layers and impurity-like transitions were studied and modeled. The effect of photovoltage in noncontact determination of electric field in semiconductor structures was determined in a novel way by studying a p-i-n diode structure. The electronic energy levels of quantum well structures were studied by photoreflectance measurements. Strained layer quantum well structures were applied to the development of high-speed semiconductor lasers. A very high modulation bandwidth of 20 GHz was obtained.