An optical method is suggested to determine the concentration of two-dimensional electrons in modulation-doped quantum wells at low and moderate electron densities between 10^{9} and 2x10^{11} cm^{-2}. The method is based on an analysis of magneto-reflectivity spectra of charged excitons (trions). The circular polarization degree and the oscillator strength of the charged excitons contain information about the density and spin polarization of two-dimensional electron gas. The method is applied to CdTe/(Cd,Mg)Te and ZnSe/Zn,Mg)(S,Se) heterostructures.
@article{arxiv.cond-mat/0111593,
title = {Optical Method for Determination of Carrier Density in Modulation Doped Quantum Wells},
author = {G. V. Astakhov and V. P. Kochereshko and D. R. Yakovlev and W. Ossau and J. Nurnberger and W. Faschinger and G. Landwehr and T. Wojtowicz and G. Karczewski and J. Kossut},
journal= {arXiv preprint arXiv:cond-mat/0111593},
year = {2009}
}