材料科学
拉曼光谱
纳米晶材料
光致发光
退火(玻璃)
透射电子显微镜
分析化学(期刊)
量子点
纳米化学
电子衍射
衍射
纳米技术
结晶学
光学
光电子学
复合材料
化学
物理
色谱法
作者
Pragati Kumar,Nupur Saxena,Ramesh Chandra,Vinay Gupta,Avinash Agarwal,D. Kanjilal
标识
DOI:10.1186/1556-276x-7-584
摘要
Nanotwin structures are observed in high-resolution transmission electron microscopy studies of cubic phase CdS quantum dots in powder form by chemical co-precipitation method. The deposition of thin films of nanocrystalline CdS is carried out on silicon, glass, and TEM grids keeping the substrates at room temperature (RT) and 200°C by pulsed laser ablation. These films are then subjected to thermal annealing at different temperatures. Glancing angle X-ray diffraction results confirm structural phase transitions after thermal annealing of films deposited at RT and 200°C. The variation of average particle size and ratio of intensities in Raman peaks I2LO/I1LO with annealing temperature are studied. It is found that electron-phonon interaction is a function of temperature and particle size and is independent of the structure. Besides Raman modes LO, 2LO and 3LO of CdS at approximately 302, 603, and 903 cm-1 respectively, two extra Raman modes at approximately 390 and 690 cm-1 are studied for the first time. The green and orange emissions observed in photoluminescence are correlated with phase transition.
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