Composition dependent nature of the fundamental optical transition in (In, Ga)As/GaP quantum dots

The nature of the ground optical transition in (In, Ga)As/GaP quantum dots is thoroughly investigated through k·p calculations and a supercell tight-binding simulation. Quantum dot morphology is deduced from scanning-tunneling-microscopy images. The strain field has a strong influence on the conduction band states. Indeed, for a pure GaAs QD, the wavefunction of the ground electron state is spatially confined in the GaP matrix, close to the dot apex, in a tensile strain region, having mainly Xz character. Time resolved and hydrostatic pressure photoluminescence experiments strongly support the theoretical conclusions. Promising results from the literature on (In, Ga)As/GaP quantum dot will be reviewed.