Analysis of the strain distribution in lateral nanostructures for interpreting photoluminescence data

The strain distribution of free-standing and buried lateral win structures based on GaAs [0 0 1] containing a In0.14Ga0.86 As single quantum well were measured by depth-resolved high-resolution grazing-incidence diffraction i n order to interprete photoluminescence (PL) results obtained from these an d similar samples. The spatial strain distribution was analyzed by running strain-sensitive in-plane scans for different penetration depths below the surface and recording the respective out-of-plane intensity curves, i.e. tr uncation rods. The 3D displacement distribution within the wires was derive d from the X-ray scattering data using a simulation on basis of the distort ed wave Born approximation taking into account the adapted parameters of a model structure generated by a finite-element calculation. Applying the def ormation potential approach the corresponding strain distribution within th e quantum well was translated into a local variation of the energy gap. Con sidering the twofold quantization and the exciton binding energy in additio n the variation of the minimum gap energy of the model structures reproduce s qualitatively the measured functional dependence of the PL-shift on the w ire width. (C) 2000 Elsevier Science B.V. All rights reserved.