Performance study of InAs/GaAs quantum dot covered by graded InxGa1 − xAs layer

InAs/GaAs quantum dots (QDs) with graded InxGa1 − xAs strained-reducing layer (SRL) are grown by metal-organic chemical vapor deposition, the effects of Indium (In) composition and thickness in InxGa1 − xAs on QD morphological characteristics and optical properties are investigated. Compared with InxGa1 − xAs SRL with fixed In content, gradient InxGa1−xAs SRL can further improve the growth quality of InAs QDs, enhance luminescence intensity and extend emission spectrum toward longer wavelength.