Impact of dopant-induced band tails on optical spectra, charge carrier transport, and dynamics in single-crystal CdTe.

Cadmium telluride (CdTe) semiconductors are used in thin-film photovoltaics, detectors, and other optoelectronic applications. For all technologies, higher efficiency and sensitivity are achieved with reduced charge carrier recombination. In this study, we use state-of-the-art CdTe single crystals and electro-optical measurements to develop a detailed understanding of recombination rate dependence on excitation and temperature in CdTe.

Dissipative Parametric Gain in a GaAs/AlGaAs Superlattice.

Parametric generation of oscillations and waves is a paradigm, which is known to be realized in various physical systems. Unique properties of quantum semiconductor superlattices allow us to investigate high-frequency phenomena induced by the Bragg reflections and negative differential velocity of the miniband electrons. Effects of parametric gain in the superlattices at different strengths of dissipation have been earlier discussed in a number of theoretical works, but their experimental demonstrations are so far absent.

High-Frequency and High-Power Performance of -Type GaN Epilayers with Low Electron Density Grown on Native Substrate.

The -type GaN epilayers with low electron density were developed on a native substrate using the metalorganic vapour phase epitaxy method and investigated under pulsed electric fields until material breakdown and optically in the spectrum range from 0.1 THz to 60 THz at two temperatures of 77 K and 300 K. The epilayers demonstrated the low-field electron mobility and density values reaching up to 1021 cm/V·s and 1.