ELECTRON-DISTRIBUTION IN PSEUDOMORPHIC AL0.30GA0.70AS IN0.15GA0.85AS/GAAS DELTA-DOPED HETEROSTRUCTURES/

We have investigated the electronic properties of the delta-modulation -doped Al0.30Ga0.70As/In0.15Ga0.85As heterojunction for a variety of d ifferent configurations. Experimental findings are compared with theor etical predictions based on the two-band effective mass approximation including strain, many-body, finite temperature, and DX center effects . We have also examined the case where the delta doping is placed in a n embedded GaAs well within the Al0.30Ga0.70As. This is intended to re duce the effects of DX centers. In this instance, as the doping concen tration is increased, experimentally determined channel density, n(s), suggests higher saturation values, which may leave a residual electro n density in the GaAs well. This residual charge density is parallel w ith the electron density in the InGaAs well and represents an addition al conducting path. The features of the theoretical channel density ve rsus doping density curves are confirmed by 300 and 1.6 K resistivity and Hall measurements, and Shubnikov-de Haas measurements made at 1.6 K.