Evidence for a Piezoelectric effect in coherently strained Ge sub (0.2) Si sub (0.8) on Si(001).

A hot carrier Shubnikov-de Haas effect has been used to measure the power loss by two-dimensional holes in coherently strained Ge sub (0.2) Si (0.8)/Si heterostructures at low temperatures. In these structures the two-dimensional hole gas resides in the Ge sub (0.2) Si sub (0.8) alloy layer. The measured power loss versus carrier temperature data are best described by the two- dimensional formulism of P. J. Price [J. Appl. Phys. 53, 6864 (1982)] which considers scattering of acoustic mode phonons. Good agreement with experiment can only be obtained if both deformation potential and piezoelectric coupling mechanisms are included.