Investigation of strain-modulated InGaAs nanostructures by grazing-incidence x-ray diffraction and photoluminescence

A strain-induced lateral periodic charge carrier confinement is achieved within an LnGaAs single quantum well (SQW) by lateral patterning of an InGaP stressor layer. The one-dimensional periodicity of the long-range strain field is obtained by etching a lateral surface grating into the initially pseudomorphicly strained InGaP layer, while the SQW itself remains unaffected by etching. Grazing incidence x-ray diffraction was applied to analyse the depth variation of the in-plane strain field within the nanostucture. The measured intensity profiles are discussed in terms of a strain distribution model, created by finite-element calculations using a linear elasticity theory approach. By photoluminescence a strain-induced shift of the SQW electronic band levels was verified. In particular a splitting of the SQW emission line was found, caused by the differently strained parts of the SQW. The photoluminescence results are compared to band structure calculations using a deformation potential ansatz.