Photoluminescence parameters in strained GaAs/In/sub x/Ga/sub 1-x/As/GaAs-heterostructures

Abstract

The photoluminescence (PL) of In/sub x/Ga/sub 1-x/As-single quantum wells (QW) grown on GaAs substrate with x ranging between 0.16 and 0.35 was studied. The thickness (d) of QW layers was about or larger than the critical one (d/sub c/). The PL parameters were found to depend on a magnitude (d-d/sub c/)/d/sub c/ if d>d/sub c/. The heterostructures with QW-thickness d not exceeding the critical one d, meets conditions of homogeneously elastically strained heterostructures almost without defects. The energy levels in QW's and PL bands (E/sub PL/) in these heterostructures may be described theoretically, and the FWHM of the band approaches its physical limit. The heterostructures with d>d/sub c/ have a defect concentration (/spl ap/10/sup 11/ cm/sup -2/) increasing with the increase of thickness. A large long-range inhomogeneous redistribution of In atoms probably occurs in the highly strained heterostructures.