Morphology and photoelectronic properties of InAs/GaAs surface quantum dots grown by metal-organic vapour-phase epitaxy

A comparative study of the surface morphology, photoluminescence, and photoelectric spectra of heterostructures with InAs/GaAs quantum dots (QDs) grown on the surface, uncovered by etching away the cladding layer, and built in the GaAs matrix is reported. The red-shift of the ground transition energy in the surface QDs compared to the built-in ones has been shown to be related not only to relaxation of the elastic strain, but also to the differences in size, shape, and chemical composition of the nanoclusters. The method of photoelectric spectroscopy in a semiconductor/electrolyte system has been applied to monitor the process of etching of the cladding layer in situ. Using this method, controlled uncovering of the buried QDs was shown to be possible. In turn, this makes it possible to study the actual morphology of the buried quantum-size layers by atomic force microscopy.