EVIDENCE OF A BLUE-SHIFT IN NEAR-SURFACE ULTRA-THIN INAS INP ISLAND LIKE QUANTUM-WELLS/

We report evidence of a large blue shift (up to 70 meV) in the photolu minescence spectra of InAs/InP island like quantum wells following the reduction of the InP top barrier layer thickness from 6 nm to near ze ro. The photoluminescence intensity only starts to decrease when the t op barrier thickness falls below 1.5 nm, indicating that radiative rec ombinations in the islands are very efficient. These results are well understood by a model assuming a vacuum confinement energy close to 5 eV. (C) 1997 American Institute of Physics.