Density and well width dependences of the effective mass of two-dimensional holes in (100) GaAs quantum wells measured using cyclotron resonance at microwave frequencies

Cyclotron resonance at microwave frequencies is used to measure the band mass (mb)(mb) of the two-dimensional holes (2DHs) in carbon-doped (100) GaAs/ AlxGa1−xAs heterostructures. The measured mbmb shows strong dependences on both the 2DH density (p)(p) and the GaAs quantum well width (W)(W). For a fixed WW, in the density range (0.4×1011 to 1.1×1011 cm−2) studied here, mbmb increases with pp, consistently with previous studies of the 2DHs on the (311)A surface. For a fixed p=1.1×1011cm−2, mbmb increases from 0.22me0.22me at W=10nm to 0.50me0.50me at W=30nm, and saturates around 0.51me0.51me for W>30nm.