@article{article, title = {{Distinguishing impurity concentrations in GaAs and AlGaAs using very shallow undoped heterostructures}}, publisher = {{AIP Publishing}}, url = {{}}, year = {{2010}}, month = {{12}}, author = {{Mak WY and Das Gupta K and Beere HE and Farrer I and Sfigakis F and Ritchie DA}}, doi = {{10.1063/1.3522651}}, volume = {{97}}, journal = {{Applied Physics Letters}}, issue = {{24}}, pages = {{242107-242107}}, note = {{Accessed on 2025/05/23}}}