BAND-STRUCTURE OF STRAINED QUANTUM-WELLS GROWN ON NOVEL INDEX SURFACES

We present a theoretical study of the in-plane valence subband structu re of unstrained GaAs-AlGaAs, compressively strained InGaAs-AlGaAs and tensile strained GaAsP-AlGaAs quantum wells grown along the (001), (1 11), (011) and (113) directions. From numerical solution of the 6 x 6 Luttinger k . p hamiltonian we find that confinement energies, warping and effective in-plane masses strongly depend on the direction of con finement and on strain. Piezoelectric effects further affect the dispe rsion for the (111) and (113) directions. Besides, we give analytic ex pressions for the heavy and light hole in-plane and perpendicular effe ctive masses for any (hkl) growth direction in the limit of uncoupled subbands.