Sheet electron density dependence of electron mobility anisotropy in In<inf>0.75</inf>Ga<inf>0.25</inf>As/InP two-dimensional electron gas

Abstract

Electron mobility anisotropy in pseudomorphic In 0.75 Ga 0.25 As/InP two-dimensional electron gas has been investigated using gated Hall-bar devices with different current-flowing directions. Clear anisotropy can be seen at both liquid He (LHe) and liquid N 2 (LN 2 ) temperatures. By using Matthiesen-type equations, isotropic and anisotropic electron mobilities and their at LHe and LN 2 temperatures, which almost monotonically increases with increasing sheet electron density. The present trends can be fitted to assumption of the random piezoelectric scattering. We also have calculated the anisotropy parameter dependence on sheet electron density have been extracted. We have found that similar trends of anisotropic electron mobility which is the ratio of isotropic and anisotropic electron mobilities. We have found that the anisotropy parameter decreases gradually with increasing sheet electron density at LN 2 temperature, and it shows a significant peak at LHe temperature.