【摘要】 利用金属有机化合物气相沉积设备生长了不同盖层结构的InAs/GaAs量子点,采用原子力显微镜和光致发光光谱仪对量子点的结构和光学性质进行了研究.量子点层之间的盖层由一个低温层和一个高温层组成.对不同材料结构的低温盖层的对比研究表明,In组分渐变的InGaAs低温盖层有利于改善量子点均匀性、减少结合岛数目、提高光致发光强度;当组分渐变InGaAs低温盖层厚度由6.8nm增加到12nm,发光波长从1256.0nm红移到1314.4nm.另外,还对不同材料结构的高温盖层进行了对比分析,发现高温盖层采用In组分渐变的InGaAs材料有利于光致发光谱强度的提高.更多还原

【Abstract】 Self-assembled InAs /GaAs quantum dot structures with different cap layers are grown by metal-organic chemical vapor deposition. The structure and optical properties of quantum dots are investigated using atomic force microscopy and photoluminescence. The cap layers sandwiched between quantum dots are composed of a low-temperature layer and a high- temperature layer. The comparative studies on low-temperature cap layer show that In graded InGaAs layer structure improves the uniformity of quantum dots, decreases coalescent islands and enhances photoluminescence intensity. Emission wavelength shifts from 1256. 0 nm to 1314. 4 nm when the thickness of graded InGaAs low-temperature cap layer increases form 6. 8 nm to 12 nm. The research on high-temperature cap layer structure indicates that In graded InGaAs layer can increase photoluminescence intensity.更多还原