Theoretical and experimental investigation of doped-channel p-type quantumwells

The influence of ionized impurity scattering on the hole mobility in delta- doped-channel AlGaAs-InGaAs quantum wells is investigated. Improvements by a factor of 2.5 were observed experimentally when moving a delta-doped impu rity plane across the quantum well towards an interface, highlighting the s cope of selective doping and wave-function engineering techniques to enhanc e the transport mobility of such devices. Theoretical hole mobility calcula tions were performed and reveal an overestimation of the transport mobility , common to the random-phase approximation (RPA), that is much stronger for p-type structures than for n-type structures. This effect is partially att ributed to an underestimation of the screening charge distribution width. U sing a lower limit for this distribution of around 50 Angstrom, it is shown that the RPA can provide accurate predictions between samples with differe nt impurity distributions and densities.