Tuning the structural and optical properties of 1.3-μm InAs/GaAs quantum dots by a combined InAlAs and GaAs strained buffer layer

摘要

A combined InAlAs and GaAs strained buffer layer was presented to tailor the structural and optical properties of 1.3-μm InAs/GaAs quantum dots. This growth technique exhibits an increment of InAs quantum-dot density from 1.6×10~(10) to 2.8×10~(10) cm~(-2) and an improvement of energy separation between the quantum-dot ground and first-excited states from 84 to 93 meV upon adjusting the thickness of GaAs in InAlAs-GaAs buffer layer. We also investigate the effect of an InAlAs layer surrounding InAs quantum dots on photoluminescence intensity with increasing the thickness of InAlAs layer in a 6-nm InAlAs-InGaAs composite cap layer, and no negative effect has been observed.