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Oscillatory behavior with magnetic field is revealed by numerical evaluation of electron scattering rates, due to reaction with interface phonon modes in semiconductor GaAs/GaAlAs quantum wells in a quantizing magnetic field. Enhancement in the width of the well reduces the scattering rate. This is not the case with bulk confined phonons.

The power loss of two-dimensional hole gas (2DHG) due to acoustic phonons via deformation potential coupling and Pekar mechanism is calculated by considering the temperature dependent screening. Hot phonon effect has reduced the power loss of 2DHG and the power loss calculations are carried out for different carrier concentrations.

A theory of free carrier absorption to explain scattering of semiconducting quantum well carriers by confined LO phonons was presented. The theory utilizes the Huang and Zhu approximation for the confinedphonon modes. The absorption coefficient was found to be similar to the calculations with bulk phonons. Absorption exhibited a well width dependence opposite that of scattering rates.

Abstract: We calculate the diffusion thermopower for a degenerate two-dimensional electron gas in real lattice-mismatched semiconductor quantum wells (QWs) at low temperatures. We consider explicitly two scattering mechanisms: (i) the surface roughness-induced piezoelectric effect, a new important scattering source, arising due to a large fluctuating density of roughness-induced piezoelectric charges and (ii) the surface roughness. The scattering parameter of energy dependence of the momentum relaxation time and the diffusion thermopower , of each of the mechanisms separately and also when both the mechanisms are combined, are calculated as a function of electron concentration and well width. The diffusion thermopower, as a function of electron concentration, due to piezoelectric field shows a change in sign for lower concentrations. Interestingly, the diffusion thermopower, due to this mechanism, as a function of well width also shows a change in sign and it is dominant for larger well widths. The numerical calculations are presented for and AlN/GaN QWs. The piezoelectric mechanism is expected to be very important in systems with large piezoelectric constant and lattice mismatch. [Copyright &y& Elsevier]