Hydrostatic pressure coefficients of the photoluminescence of InAs/GaAs quantum dots

There is a significant diminution in the hydrostatic pressure coefficients (PCs) of the photoluminescence spectrum for InAs/GaAs quantum dots in comparison with that of bulk binary. We study this phenomenon with the nonlinear elasticity theory. The variation of the lattice and elastic constants plays an important role in the change of PCs, which causes the obvious decrease of the built-in strains of InAs/GaAs quantum dots under the hydrostatic pressure. The decrease will induce the novel change of the energy gap and the electronic confined energy. Finally, the change is shown in the measured small PCs of photoluminescence from quantum dots. Also the calculation reveals that the PCs are sensitive to the sizes of quantum dots because of the change of the electronic confined energy. The smaller the quantum dot is, the stronger the influence of this change on the PCs becomes. This effect gives rise to the increase of PCs when dot size is reduced.