The photoluminescence spectra of InAs quantum dots (QDs) embedded into four types of InxGa1-xAs/GaAs (x = 0.10, 0.15, 0.20 and 0.25) multi quantum well MBE structures have been investigated at 300 K in dependence on the QD position on the wafer. PL mapping was performed with 325 nm HeCd laser (35 mW) focused down to 200 mu m (110 W/cm(2)) as the excitation source. The structures with x = 0.15 In/Ga composition in the InxGa1-xAs capping layer exhibited the maximum photoluminescence intensity. Strong inhomogeneity of the PL intensity is observed by mapping samples with the In/Ga composition of x >= 0.20-0.25. The reduction of the PL intensity is accompanied by a gradual "blue" shift of the luminescence maximum at 300 K as follows from the quantum dot PL mapping. The mechanism of this effect has been analyzed. PL peak shifts versus capping layer composition are discussed as well. (c) 2006 Elsevier B.V. All rights reserved.