Two-Dimensional Electron Gas in InGaAs/InAlAs Quantum Wells

We designed and performed low temperature DC transport characterization studies on two-dimensional electron gases confined in lattice-matched In${}_{0.53}$Ga${}_{0.47}$As/In${}_{0.52}$Al${}_{0.48}$As quantum wells grown by molecular beam epitaxy on InP substrates. The nearly constant mobility for samples with the setback distance larger than 50nm and the similarity between the quantum and transport life-time suggest that the main scattering mechanism is due to short range scattering, such as alloy scattering, with a scattering rate of 2.2 ps${}^{-1}$. We also obtain the Fermi level at the In${}_{0.53}$Ga${}_{0.47}$As/In${}_{0.52}$Al${}_{0.48}$As surface to be 0.36eV above the conduction band, when fitting our experimental densities with a Poisson-Schr"odinger model.