Electron mobility enhancement by confining optical phonons in GaAs/AlAs multiple quantum wells

Abstract

We report experimental evidence for an enhanced electron mobility in a multiple quantum well structure in which the optical phonon modes are confined. By inserting n ultrathin layers of AlAs into a host GaAs well, thus dividing the bulklike host well into n+1 miniwells, we observe a substantial enhancement in electron mobility for temperatures T≳100 K. We have also studied the dependence of the electron mobility on the miniwell width. The electron mobility is found to first increase with decreasing miniwell width and then decrease after reaching a maximum value at the width around 45 Å.