BAND-STRUCTURE OF VERY NARROW INGAAS INP QUANTUM-WELLS WITH GRADUAL INTERFACE EFFECTS/

Band structure calculations are performed on narrow InGaAs/InP quantum wells (QWs) including gradual interface effects. Within the confines of the envelope approximation, the transfer matrix method is used, wit h adaptation to multi-band models. A comparison is made for two struct ures with fundamental absorption edges near 1.3 mu m, an abrupt eight monolayers (ML)-wide lattice-matched Ln(0.532)Ga(0.468)As/InP QW, as a reference, and a QW with a gradual profile because of interface effec ts. With respect to the reference QW, the inplane electron effective m ass in the gradual structure is slightly higher. The distance between heavy hole (HH) and light hole (LH) subbands is enhanced. Due to an as ymmetric profile, a splitting occurs for the hole subbands, equivalent to that induced by a 500 kV cm(-1) electric field in the reference QW . The KH in-plane effective mass is not significantly affected by the interface effects. For LHs, the upper branch remains electron-like and the associated in-plane effective mass is slightly reduced (in absolu te value), while the lower branch is hole-like with a large value of e ffective mass. (C) 1997 Academic Press Limited.