Impurity free vacancy disordering of InGaAs quantum dots

Abstract

The effect of thermal interdiffusion on In(Ga)As∕GaAsquantum dot structures is very significant, due to the large strain and high concentration of indium within the dots. The traditional high temperature annealing conditions used in impurity free vacancy disordering of quantum wells cannot be used for quantum dots, as the dots can be destroyed at these temperatures. However, additional shifts due to capping layers can be achieved at low annealing temperatures. Spin-on-glass, plasma enhanced chemical vapor depositedSiO₂, Si₃N₄, and electron-beam evaporated TiO₂ layers are used to both enhance and suppress the interdiffusion in single and stacked quantum dot structures. After annealing at only 750°C the different cappings enable a shift in band gap energy of 100meV to be obtained across the sample. Show more