Suppressing electron scattering is essential to achieve high-mobility two-dimensional electron systems (2DESs) that are clean enough to probe exotic interaction-driven phenomena. In heterostructures it is common practice to utilize modulation doping, where the ionized dopants are physically separated from the 2DES channel. The doping-well structure augments modulation doping by providing additional screening for all types of charged impurities in the vicinity of the 2DES, which is necessary to achieve record-breaking samples. Despite its prevalence in the design of ultra-high-mobility 2DESs, the working principles of the doping-well structure have not been reported. Here we elaborate on the mechanics of electron transfer from doping wells to the 2DES, focusing on GaAs/AlGaAs samples grown by molecular beam epitaxy. Based on this understanding we demonstrate how structural parameters in the doping well can be varied to tune the properties of the 2DES.
@article{arxiv.2004.08674,
title = {Working principles of doping-well structures for high-mobility two-dimensional electron systems},
author = {Yoon Jang Chung and K. A. Villegas Rosales and K. W. Baldwin and K. W. West and M. Shayegan and L. N. Pfeiffer},
journal= {arXiv preprint arXiv:2004.08674},
year = {2020}
}