Diffusivity transients and radiative recombination in intermixed In0.5Ga0.5As/GaAs quantum structures

Abstract

The effects of thermally induced compositional disordering on the luminescence from two-dimensional and zero-dimensional ${\mathrm{In}}_{0.5}{\mathrm{Ga}}_{0.5}\mathrm{A}\mathrm{s}/\mathrm{G}\mathrm{a}\mathrm{A}\mathrm{s}$ structures are examined. Quantum-mechanical numerical calculations modeling changes in the quantum-well (QW) confining potential with interdiffusion have been used to obtain values for diffusivities. These show transient behavior. Activation energies for interdiffusion (3.5±0.3 eV) are found to be similar to values reported for low-indium-content ${\mathrm{In}}_x{\mathrm{Ga}}_{1-x}As/$GaAs QW’s. In quantum-dot structures, larger blueshifts can be obtained than in QW’s under similar conditions. Interdiffusion decreased activation energies for radiative recombination, reflecting changes in confining potentials, and affecting lifetime ratios in recombination processes. The latter were observed in all intermixed heterostructures regardless of dimensionality.