Two‐dimensional electron gas mobility anomalies (and enhancement) in pseudomorphic AlGaAs/InGaAs/GaAs heterostructures Available to Purchase

Variation of two‐dimensional electron gas mobility with carrier concentration n_s has been examined for different modulation‐doped heterostructures of AlGaAs/InGaAs/GaAs. It is demonstrated that, depending on the method, electrons are distributed among remote impurity sites and different values of mobility can be achieved for the same n_s and in the same heterostructure. The origin of this finding is associated with the spatial correlations of remote impurity charges which form dipolelike objects consisting positively charged Si donors and negatively charged DX⁻ states of the same donor. The effect of correlations causes enhancement of mobility of the order of tens of percent and can explain the appearance of the maximum on a mobility versus n_s dependence.