BAND NONPARABOLICITIES IN LATTICE-MISMATCH-STRAINED BULK SEMICONDUCTOR LAYERS

Analytic expressions for band nonparabolicities and effective masses are derived for lattice-mismatch-strained bulk semiconductor layers. We have investigated both a full 6×6 valence-band Hamiltonian and an 8×8 model. In the latter, the interactions between the singlet conduction band and the triplet valence bands were treated exactly, with the effects of higher bands calculated to order k2. To our knowledge, the present work constitutes the first explicit calculation of strain and kp matrix elements using a basis consistent with the formalism of Luttinger and Kohn [Phys. Rev. 97, 869 (1955)] throughout. The present results should prove to be valuable in determining strained-layer heterostructure band alignments using excitation spectroscopy and in applications requiring highly accurate estimates of confinement energies in narrow quantum-well structures (such as those used in long-wavelength infrared detection). © 1990 The American Physical Society.