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 (m(b)) of the two-dimensional holes (2DHs) in carbon-doped (100) GaAs/AlxGa1-xAs heterostructures. The measured m(b) shows strong dependences on both the 2DH density (p) and the GaAs quantum well width (W). For a fixed W, in the density range (0.4 X 10(11) to 1.1 X 10(11) cm(-2)) studied here, m(b) increases with p, consistently with previous studies of the 2DHs on the (311)A surface. For a fixed p = 1.1 x 10(11) cm(-2), m(b) increases from 0.22m(e) at W = 10 nm to 0.50m(e) at W = 30 nm, and saturates around 0.51m(e) for W > 30 nm. (c) 2007 Elsevier Ltd. All rights reserved.