Confinement effects in PbSe quantum wells and nanocrystals
Confinement effects in PbSe quantum wells and nanocrystals
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DOI：
10.1103/physrevb.70.245321
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发表时间：
2004-12-01
影响因子：
3.7
通讯作者：
Delerue, C
中科院分区：
文献类型：
--
作者：
Allan, G;Delerue, C
采用紧密结合计算方法研究了量子约束对硒量子阱和量子点的影响。与锌-闪锌矿半导体相比，岩盐PbSe纳米结构具有不同寻常的物理性质。对于井和点，能隙的增大与尺寸成反比。对于PbSe纳米晶体，其发光寿命、约束能和带内光学性质与实验结果一致。实验观察到的高量子产率可以用这些体系中没有表面悬空键来解释。讨论了吸收光谱中测量到的第二峰的起源，而S-P带间跃迁表现出非常小的振荡器强度。计算了全频率相关的介电函数epsilon（omega）。它的虚部epsilon(2)（ω）具有很强的各向异性，即使远离间隙区，其体积值也表现出很大的变化。
The effect of quantum confinement in PbSe quantum wells and dots is studied using tight binding calculations. Compared to zinc-blende semiconductors, unusual physical properties are predicted for rock salt PbSe nanostructures. The energy gap increases as the inverse of the size both for wells and dots. For PbSe nanocrystals, the luminescence lifetime, the confinement energy, and the intraband optical properties are in good agreement with experiments. The high quantum yield observed experimentally can be explained by the absence of surface dangling bonds in these systems. The origin of the second peak measured in the absorption spectra is discussed, whereas S-P interband transitions exhibit very small oscillator strength. The full frequency-dependent dielectric function epsilon(omega) is calculated for PbSe quantum wells. Its imaginary part epsilon(2)(omega) is strongly anisotropic and shows large variations with respect to its bulk value even far from the gap region.