Hall-effect measurements in p-type InGaAs/GaAs strained-layer superlattices

We report, for the first time, temperature-dependent Hall data for holes in modulation-doped In/sub 0.2/Ga/sub 0.8/As/GaAs strained-layer superlattices. Samples with (compressive) planar strains of -0.5% to -1.2% in the InGaAs quantum wells were used, providing a range of configurations for the two (overlapping) sets of valence-band quantum wells derived from the bulk heavy- and light-hole bands. All samples exhibit transfer of holes into the InGaAs quantum wells at low temperature; however, the sample with the least strain shows evidence for gradual carrier freeze-out over a wide range of temperature