We report on a systematic investigation of the dominant scattering mechanism in shallow two-dimensional electron gases (2DEGs) formed in modulation-doped GaAs/Al_{x}Ga_{1-x}As heterostructures. The power-law exponent of the electron mobility versus density, mu \propto n^{alpha}, is extracted as a function of the 2DEG's depth. When shallower than 130 nm from the surface, the power-law exponent of the 2DEG, as well as the mobility, drops from alpha \simeq 1.65 (130 nm deep) to alpha \simeq 1.3 (60 nm deep). Our results for shallow 2DEGs are consistent with theoretical expectations for scattering by remote dopants, in contrast to the mobility-limiting background charged impurities of deeper heterostructures.
@article{arxiv.0908.2104,
title = {Scattering Mechanism in Modulation-Doped Shallow Two-Dimensional Electron Gases},
author = {D. Laroche and S. Das Sarma and G. Gervais and M. P. Lilly and J. L. Reno},
journal= {arXiv preprint arXiv:0908.2104},
year = {2010}
}
Comments
4 pages, 3 figures, modified version as accepted in APL