Carrier velocity-field characteristics and alloy scattering potential in Si1−<i>x</i>Ge<i>x</i>/Si

Abstract

The alloy scattering potential is an important parameter in SiGe alloys since it not only affects the velocity-field characteristics for carrier transport, but also allows increased optical transitions by relaxing k-selection rules. In this letter, we report on the velocity-field measurements for relaxed and coherently strained SiGe alloys. The alloy scattering potential is obtained from a careful fit to the data. The hole velocity at any field is found to have a bowing behavior as a function of alloy composition. This reflects a strong alloy scattering potential which is calculated to be 0.6 eV for the valence band.