ABSORPTION IN P-TYPE SI-SIGE STRAINED-QUANTUM-WELL STRUCTURES

We present full-wale relativistic pseudopotential calculations of the first-order susceptibility in p-type si-SiGe structures with a view of exploring the suitability of such systems for infrared (10-15 and 3-5 mum wavelengths) applications. The frequency dependence of the linear response due to transitions between valence minibands is calculated a nd the microscopic origin of the peaks determined. We also explore the effect of temperature on various structures. We show that simple part icle-in-a-box models are unable to correctly describe the observed pea k positions or the mechanisms involved. In particular, many important contributions come from areas of the Brillouin zone away from the zone center. We sis to show that normal incidence absorption is possible u sing SiGe structures.