Electron mobility enhancement from coupled wells in delta-doped GaAs

Abstract

It is found that when two Si delta (δ) doped wells in GaAs are placed in close proximity to one another, the electron Hall mobility is enhanced two to five times over that of the single well case. The temperature dependence of the mobility is also reported. Samples with a variety of spacer widths have been studied. Our theoretical and experimental data show that the excited subbands in the double well structure have significant carrier densities located in the undoped region where Coulombic scattering is reduced, and are thus found to play an important role in the observed mobility behavior.