Energy Levels of InGaAs/GaAs Quantum Dot Lasers with Different Sizes

Abstract

<em>In this paper, we have studied the strain, band-edge, and energy levels of cubic InGaAs quantum dots (QDs) surrounded by GaAs. It is shown that overall strain value is larger in InGaAs-GaAs interfaces, as well as in smaller QDs. Also, it is proved that conduction and valence band-edges and electron-hole levels are size dependent; larger QD sizes appeared to result in the lower recombination energies. Moreover, more number of energy levels separate from the continuum states of bulk GaAs and come down into the QD separate levels. In addition, we show that change of band gap and energy level by size is not linear, i.e., band gap and energy level in smaller QDs are more sensitive to QD size. Our results coincide with former similar researches.</em>