A first-principles study of II-VI (II = Zn; VI = O, S, Se, Te) semiconductor nanostructures
A first-principles study of II-VI (II = Zn; VI = O, S, Se, Te) semiconductor nanostructures
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DOI：
10.1039/c2jm33744d
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发表时间：
2012-10-28
影响因子：
--
通讯作者：
De Angelis, Filippo
中科院分区：
文献类型：
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作者：
Azpiroz, Jon M.;Infante, Ivan;De Angelis, Filippo
我们在 DFT/TDDFT 理论水平上对类纤锌矿 ZnX（X = O、S、Se、Te）纳米结构的结构、电子和光学性质进行了系统研究。为了与实验进行直接比较，我们已经从本体中构建了真实的 1.0-1.5 nm 量子点。低位计算的激发能与现有的实验数据非常吻合。半导体量子点典型的宽激发曲线和窄发射光谱可以通过以下事实来解释：LUMO 是接受计算出的低位 TDDFT 激发的电子的状态。计算得出的 Zn 3d 壳的结合能比相应块体材料的结合能低 0.5 eV。阴离子空位可以通过在纳米结构的带隙中引入陷阱态来解释 ZnX 的可见光发射，这与之前关于 ZnO 的理论和实验工作一致。对棒状和片状原型团簇的计算表明，量子限制对锌基纳米材料的光电性能具有显着的影响。
We present a systematic investigation of the structural, electronic and optical properties of wurtzite-like ZnX (X = O, S, Se, Te) nanostructures at the DFT/TDDFT level of theory. To provide a direct comparison with the experiment, realistic 1.0-1.5 nm quantum dots have been built up from the bulk. Low-lying computed excitation energies agree well with the available experimental data. The broad excitation profiles and narrow emission spectra typical of semiconductor quantum dots could be explained by the fact that the LUMO is the state accepting the electron of the low-lying TDDFT excitations calculated. Calculated binding energies for the Zn 3d shell have been found to be 0.5 eV lower than those of the corresponding bulk materials. Anion vacancies can explain the visible light emission of ZnX by introducing a trap state into the bandgap of the nanostructures, in agreement with previous theoretical and experimental works on ZnO. Calculations on rod- and sheet-like prototype clusters point to a significant quantum confinement effect on the optoelectronic properties of Zn-based nanomaterials.