Photoluminescence parameters in strained GaAs/InxGa1-xAs/GaAs-heterostructures

The photoluminescence (PL) of In_xGa_1-xAs-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 _c). The PL parameters were found to depend on a magnitude (d-d_c)/d_c if d>d_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_PL ) in these heterostructures may be described theoretically, and the FWHM of the band approaches its physical limit. The heterostructures with d>d_c have a defect concentration (≈10¹¹ cm^-2) increasing with the increase of thickness. A large long-range inhomogeneous redistribution of In atoms probably occurs in the highly strained heterostructures