GENERALIZATION OF THE K-CENTER-DOT-P APPROACH FOR STRAINED LAYERED SEMICONDUCTOR STRUCTURES GROWN ON HIGH-INDEX-PLANES

We present a generalized theoretical description of the 8 X 8 k . p ap proach for determining the band structure of layered semiconductor str uctures for any growth direction, including strain and piezoelectric e ffects. The definition of heavy, light, and splitoff hole states is ex tended to arbitrary growth directions in analogy to the conventional ( 001) case, by choosing an adapted set of basis functions. The choice o f this basis allows a qualitative understanding of the in-plane band s tructure and of the optical properties of strained and unstrained stru ctures. Besides, we solve the k . p Hamiltonian by means of an efficie nt real-space method allowing us to deal with arbitrary confining pote ntials. The theory is applied to unstrained, compressively strained, a nd tensilely strained quantum wells. We find that confinement energies , warping, and in-plane effective masses strongly depend on the direct ion of confinement and on strain. Piezoelectric effects further affect the dispersion for all growth directions other than (001) and (011). We also find that the optical transition strength depends on the in-pl ane light polarization for growth directions other than (001) and (111 ).