Valence Band Properties of Relaxed Ternary Group IV Semiconductor Alloys

Abstract

We report calculations of valence band properties of ternary group IV semiconductor alloys Si1-x-yGexCy. The linear combination of atomic orbitals' Hamiltonian matrix with spin-orbit interaction terms is incorporated to obtain the analytic expression for the valence band structure for all the calculations. The anisotropy parameter Γ of the valence band, the density-of-state effective masses (d.o.s. m*) of holes are calculated as functions of alloy concentration x and y. The cyclotron resonance effective masses (CR m*) of holes are also calculated as a function of x, y, and the angle θ between the static magnetic field in (110) plane and [001] axis. A sharp rise of the values of Γ, d.o.s. m*, and CR m* for fixed θ for heavy holes are found as the alloy approaches pure diamond while the light hole values vary moderately over all the alloy concentrations. Our calculations provide a strong evidence that the interaction between the split-off hole band and the heavy hole band is responsible for the anomalous behavior of the heavy holes properties.