CONDUCTION-BAND AND VALENCE-BAND STRUCTURES IN STRAINED IN1-XGAXAS INP QUANTUM-WELLS ON (001) INP SUBSTRATES/

We study conduction-band and valence-band structures in strained In1-x GaxAs/InP quantum wells on (001) InP substrates using the k.p perturba tion approach and magneto-optical absorption measurements. We evaluate the band offset between In1-xGaxAs and InP using the tight-binding mo del. We derive a formula for calculating conduction-band dispersion bo th in biaxially strained bulk layers and quantum wells from the first- order k.p perturbation. We use our formula to show that the electron e ffective mass of strained In1-xGaxAs and strained In1-xGaxAs/InP quant um wells are anisotropic, and that the masses depend significantly on the strain and well width. We evaluate magneto-optical absorption spec tra of multiple quantum wells with compositions, x, from 0.34 to 0.58, corresponding to about +/- 1% in-plane strain, and with well widths f rom 6 to 14 nm. We analyze the diamagnetic shifts of exciton resonance s based on the effective-mass equations taking both conduction- and va lence-band nonparabolic dispersion into account. We obtain in-plane el ectron, hole, and reduced effective masses of excitons and Luttinger-K ohn effective-mass parameters for valence bands as a function of compo sition.