자발성형 InAs/GaAs 양자점의 구조 및 성장 특성

Abstract

Self-assembled InAs/GaAs quantum dots (QDs) were grown by molecular beam epitaxy and the growth characteristics of QDs were studied using field emission gun-electron transmission microscope. The shapes and optical properties of QDs changed according to spacer layers thickness due to the strain between InAs and GaAs layers. The QDs with 50 nm thick GaAs spacer layers were distributed randomly along the growth direction and changed from dome to flat-pyramidal shape after capping with GaAs. However, QDs with 10 nm thick spacer layers were vertically aligned up to the fifth period and the dome-shape was maintained after capping. The density, distribution and crystalline defects depending on growth conditions were also investigated.