Semiconductor quantum dot superlattices (QDSLs) have attracted much attention as key materials for realizing new optoelectronic devices such as solar cells with high conversion efficiency and thermoelectric elements with high electrical conductivity. To improve the charge transport properties of QDSL-based optoelectronic devices, it is important that the QD structures form minibands, which are the coupled electronic states between QDs. A shorter inter-QD distance and a periodic arrangement of QDs are the essential conditions for the formation of minibands. In this study, we use CdTe QDs capped with short ligands of N-acetyl-L cysteine (NAC) to fabricate three-dimensional QD assemblies by utilizing chemical bonding between NACs. Absorption spectra clearly display the quantum resonance phenomenon originating from the coupling of the wave functions between the adjacent QDs in CdTe QD assemblies. Furthermore, we demonstrate the formation of minibands in CdTe QD assemblies by examining both, the excitation energy dependence of photoluminescence (PL) spectra and the detection energy dependence of PL excitation spectra. The fabrication method of QD assemblies utilizing chemical bonding between NACs can be applied to all QDs capped with NAC as a ligand.

中文翻译：

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利用配体之间的化学键制造的CdTe量子点组件中的耦合电子态

作为实现新型光电器件的关键材料，半导体量子点超晶格（QDSL）引起了人们的极大关注，例如具有高转换效率的太阳能电池和具有高电导率的热电元件。为了提高基于QDSL的光电设备的电荷传输性能，重要的是QD结构形成微带，这些微带是QD之间的耦合电子状态。较短的QD间距离和QD的​​周期性排列是形成微带的必要条件。在这项研究中，我们使用的CdTe量子点被N-乙酰基-L的短配体封端半胱氨酸（NAC）通过利用NAC之间的化学键来制造三维QD组件。吸收光谱清楚地显示了量子共振现象，该现象源自CdTe QD组件中相邻QD之间波函数的耦合。此外，我们通过检查光致发光（PL）光谱的激发能量依赖性和PL激发光谱的检测能量依赖性，证明了CdTe QD组件中微带的形成。利用NAC之间化学键合的QD组件的制造方法可以应用于所有以NAC为配体的QD。