Electron transport in an In$_{0.52}$Al$_{0.48}$As/In$_{0.53}$Ga$_{0.47}$As/In$_{0.52}$Al$_{0.48}$As quantum well with a $\delta$-Si doped barrier in high electric fields

The electron conduction in a two-dimensional channel of an In$_{0.52}$Al$_{0.48}$As/In$_{0.53}$Ga$_{0.47}$As/In$_{0.52}$Al$_{0.48}$As quantum well (QW) with a $\delta$-Si doped barrier has been investigated. It is shown that the introduction of thin InAs barriers into the QW reduces the electron scattering rate from the polar optical and interface phonons localized in the QW and increases the electron mobility. It is found experimentally that the saturation of the conduction current in the In$_{0.53}$Ga$_{0.47}$As channel in strong electric fields is determined by not only the sublinear field dependence of the electron drift velocity, but also by the decrease in the electron concentration $n_s$ with an increase in the voltage across the channel. The dependence of $n_s$ on the applied voltage is due to the ionized-donor layer located within the $\delta$-Si doped In$_{0.52}$Al$_{0.48}$As barrier and oriented parallel to the In$_{0.53}$Ga$_{0.47}$As QW.