Condensed Matter Physics Division, Indira Gandhi Centre for Atomic Research, Tamil Nadu 603102, India.
J Phys Chem B. 2010 Apr 1;114(12):4199-203. doi: 10.1021/jp912103t.
The size stability of nanoparticles is crucial from an application point of view. We probe, using Raman spectroscopy, particle size evolution of CdS nanoparticles by varying laser power. Multiphonon resonant Raman scattering has also been demonstrated. With increase in laser power, the intensity ratio of 2-longitudinal optical (LO) to 1-LO is found to increase dramatically, and LO phonon overtones up to fourth order are observed. Resonant Raman scattering has been achieved by suitably matching the band gap with the excitation photon energy, by varying the local temperature. The effect of increase in local temperature on the band gap is also discussed.
从应用的角度来看，纳米粒子的尺寸稳定性至关重要。我们使用拉曼光谱探测通过改变激光功率时 CdS 纳米粒子的粒径演变。还证明了多声子共振拉曼散射。随着激光功率的增加，发现 2 纵光学（LO）与 1-LO 的强度比急剧增加，并且观察到 LO 声子的倍频高达四阶。通过适当匹配带隙与激发光子能量，通过改变局部温度，实现了共振拉曼散射。还讨论了局部温度对带隙的影响。
