Miah M Idrish
Nanoscale Science and Technology Centre, School of Biomolecular and Physical Sciences, Griffith University, Nathan, Brisbane, QLD 4111, Australia.
J Phys Chem B. 2009 Feb 12;113(6):1652-4. doi: 10.1021/jp807944y.
Photoinduced second harmonic generation (PISHG) in undoped as well as in various Cu-doped (0.05-1.2% Cu) CdI2 nanocrystals was measured at liquid nitrogen temperature (LNT). It was found that the PISHG increases with increasing Cu doping up to approximately 0.6% and then decreases almost to that for the undoped CdI2 for doping higher than approximately 1%. The values of the second-order susceptibility ranged from 0.50 to 0.67 pm V(-1) for the Cu-doped nanocrystals with a thickness of 0.5 nm. The Cu-doping dependence shown in a parabolic fashion suggests a crucial role of the Cu agglomerates in the observed effects. The PISHG in crystals with various nanosizes was also measured at LNT. The size dependence demonstrated the quantum-confined effect with a maximum PISHG for 0.5 nm and with a clear increase in the PISHG with decreasing thickness of the nanocrystal. The Raman scattering spectra at different pumping powers were taken for thin nanocrystals, and the phonon modes originating from interlayer phonons were observed in the spectra. The results were discussed within a model of photoinduced electron-phonon anharmonicity.
在液氮温度（LNT）下测量了未掺杂以及各种铜掺杂（0.05 - 1.2% Cu）的CdI2纳米晶体中的光致二次谐波产生（PISHG）。发现PISHG随着铜掺杂量增加至约0.6%而增加，然后对于高于约1%的掺杂，其几乎降至未掺杂CdI2的水平。对于厚度为0.5 nm的铜掺杂纳米晶体，二阶极化率的值在0.50至0.67 pm V(-1)范围内。以抛物线形式呈现的铜掺杂依赖性表明铜团聚体在观察到的效应中起关键作用。在LNT下还测量了具有各种纳米尺寸的晶体中的PISHG。尺寸依赖性显示出量子限制效应，对于0.5 nm的晶体PISHG最大，并且随着纳米晶体厚度减小PISHG明显增加。对薄纳米晶体在不同泵浦功率下进行了拉曼散射光谱测量，并且在光谱中观察到了源自层间声子的声子模式。在光致电子 - 声子非谐性模型内对结果进行了讨论。
