Energy loss rates of two-dimensional hole gases in inverted Si/Si0.8Ge0.2 heterostructures

We have investigated the energy loss rate of hot holes as a function of car rier temperature T-C in p-type inverted modulation-doped (MD) Si/SiGe heter ostructures over the carrier sheet density range (3.5-13) x 10(11) cm(-2), at lattice temperatures of 0.34 and 1.8 K. It is found that the energy loss rate (ELR) depends significantly upon the carrier sheet density, n(2D). Su ch an n(2D) dependence of ELR has not been observed previously in p-type Si Ge MD structures. The extracted effective mass decreases as n(2D) increases , which is in agreement with recent measurements on a gated inverted sample . It is shown that the energy relaxation of the two-dimensional hole gases is dominated by unscreened acoustic phonon scattering and a deformation pot ential of 3.0 +/- 0.4 eV is deduced. (C) 2000 American Institute of Physics . [S0003-6951(00)02809-6].