INTERFACE INEQUIVALENCE OF THE INP INALAS/INP STAGGERED DOUBLE-HETEROSTRUCTURE GROWN BY METALORGANIC CHEMICAL-VAPOR-DEPOSITION/

The optical and structural properties of the normal InAlAs on InP and the inverted InP on the InAlAs staggered band lineup interface grown b y metalorganic chemical vapor deposition (MOCVD) are compared by use o f transmission electron microscopy (TEM), time integrated, and time re solved photoluminescence. TEM images show that both interfaces are dis similar. The normal interface is very abrupt. The inverted interface s hows an additional graded layer of about 2.5 nm in width of In1-xAlxAs yP1-y with x (0.48-0) and y (1.0-0.0). A large optical anisotropy exis ts because of the inequivalence of the two interfaces. The larger spat ial separation of the carriers at the inverted interface is responsibl e for a smaller overlap of the electron and hole wave functions and fo r that reason a one order of magnitude longer e-h luminescence decay t ime of 45 ns is observed. The normal interface transition shifts appro ximately to the third root of excitation while the inverted interface transition shifts logarithmically. (C) 1996 American Institute of Phys ics.