Electron cyclotron resonance in silicon/silicon germanium heterostructures

Far-infrared measurements of the cyclotron resonance absorption of a two-dimensional electron gas (2DEG) in a strained Si/SiGe heterostructure at low temperature (0.35-4 K) in the magnetic field range 2-14 T are reported. The effective mass was determined to be m*≅0.195±0.004 m 0, and exhibited only a slight decrease (3%) at low carrier densities, in contrast to the large (40%) change observed in Si metal-oxide-semiconductor field effect transistors. In addition, the cyclotron absorption lines tend to be narrow (≲1 cm-1), and show a significant dependence on both field and carrier density that appears to be related to the filling of the quantized Landau and spin levels of the 2DEG.