Study of quasi-two-dimensional hole gas in Si/Si_xGe_1-x/Si quantum wells

Quasi-two-dimensional hole gas in strained Si/Si_xGe_1-x/Si quantum well structure is investigated both theoretically and experimentally. The hole effective mass and the charge distribution in the structure are obtained from the self-consistent solution of the Schrödinger-Poisson equations. The calculation results show the dependence of the averaged mass on the measurement temperature and the averaged mass of 0.20 m₀ at T = 4 K. High quality Si/Si_0.8Ge_0.2/Si p-type modulation-doped quantum well is grown by molecular beam epitaxy and the electrical properties measured. Hall mobility as high as ∼10,400 cm²/V·s with a sheet carrier concentration of ∼ 1.1 × 10¹² cm^-2 and an effective mass of ∼ 0.30 m₀ is obtained at T = 4 K.