InGaAs/GaAs量子阱中自组装InAs量子点的光学性质

在InGaAs/GaAs量子阱中生长了两组InAs量子点样品,用扫描电子显微镜(SEM)测量发现,量子点呈棱状结构,而不是通常的金字塔结构,这是由多层结构的应力传递及InGaAs应变层的各向异性引起的.采用变温光致发光谱(TDPL)和时间分辨谱(TRPL)研究了其光致发光稳态和瞬态特性.研究发现,InGaAs量子阱层可以有效地缓冲InAs量子点中的应变,提高量子点的生长质量,可以在室温下探测到较强的发光峰.在量子阱中生长量子点可以获得室温下1 318 nm的发光,并且使其PL谱的半高宽减小到25 meV.

Photoluminescence Characteristics of InAs Self-assembled Quantum Dots in InGaAs/GaAs Quantum Well

Two types of InAs quantum dots grown in InGaAs/GaAs quantum well(DWELL) were fully investigated by time-resolved(TR) and temperature dependent photoluminescence(TDPL).Scanning electron microscopy(SEM) measurements show that the shape of quantum dots is prismatic,but not the common pyramid shape.We consider that it is attributed to stress transition of multi-layer structure and anisotropy of InGaAs strained layer.DWELL structures could combine both the effects of InGaAs buffer layer and cap layer and even effectively release the stress between the buffer layer and the QDs, which may greatly improve the QDs quality.Strong PL signal emitting at 1 318 nm can be detected at room temperature and the full width at half maximum of PL spectrum is only 25 meV at some temperature.