Two-dimensional warm-electron transport in GaAs and In1-xGaxAs quantum wells at low temperatures.

Abstract

The warm-electron coefficient and mobility of the two-dimensional electron gas in a square quantum well (QW) of GaAs and ${\mathrm{In}}_{0.53}$${\mathrm{Ga}}_{0.47}$As are studied over the temperature range 5 to 25 K. The effects of ionized-impurity, deformation-potential acoustic, and piezoelectric scattering are included in the framework of Fermi-Dirac statistics considering screening and nonequipartition of phonons. Scattering by alloy disorder is also included for ${\mathrm{In}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Ga}}_{\mathit{x}}$As. The Ohmic mobility for GaAs and ${\mathrm{In}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Ga}}_{\mathit{x}}$As QW's is found to be controlled predominantly by ionized-impurity and alloy scatterings, respectively. The warm-electron coefficient is shown to be positive for a GaAs and negative for an ${\mathrm{In}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Ga}}_{\mathit{x}}$As QW. Its magnitude decreases with increasing temperature and is larger for larger widths of the QW.