Univiversity Lille, CNRS, Centrale Lille, ISEN, University Valenciennes , UMR 8520-IEMN, F-59000 Lille, France.
Nano Lett. 2017 Dec 13;17(12):7599-7605. doi: 10.1021/acs.nanolett.7b03605. Epub 2017 Dec 5.
The optical response of ZnO nanocrystals (NCs) doped with Al (Ga) impurities is calculated using a model that incorporates the effects of quantum confinement, dielectric mismatch, surface, and ionized impurity scattering. For dopant concentrations of a few percent, the NC polarizability is dominated by a localized surface plasmon resonance (LSPR) in the infrared (IR) which follows the Drude-Lorentz law for NC diameter above ∼10 nm but is strongly blue-shifted for smaller diameters due to quantum confinement effects. The intrinsic width of the LSPR peak is calculated in order to characterize plasmon losses induced by ionized impurity scattering. Widths below 80 meV are found in the best cases, in agreement with the lowest values recently measured on single NCs. These results confirm that doped ZnO NCs are very promising for the development of IR plasmonics. The width of the LSPR peak strongly increases when dopants are placed near the surface of the NCs or when additional fixed charges are present.
采用一种将量子限制、介电失配、表面和离子杂质散射效应综合起来的模型，计算了掺杂 Al（Ga）杂质的 ZnO 纳米晶（NCs）的光学响应。对于百分之几的掺杂浓度，NC 的极化率主要由红外（IR）中的局域表面等离子体共振（LSPR）主导，对于直径大于 ∼10nm 的 NC，其遵循 Drude-Lorentz 定律，但由于量子限制效应，对于较小的直径，其会强烈蓝移。为了表征由离子杂质散射引起的等离子体损耗，计算了 LSPR 峰的固有宽度。在最好的情况下，发现宽度低于 80meV，这与最近在单个 NC 上测量的最低值一致。这些结果证实了掺杂 ZnO NCs 在开发 IR 等离子体学方面非常有前景。当掺杂剂放置在 NC 表面附近或存在额外的固定电荷时，LSPR 峰的宽度会强烈增加。
