N-type colloidal semiconductor nanocrystals
N-type colloidal semiconductor nanocrystals
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DOI：
10.1038/35039577
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发表时间：
2000-10-26
期刊：
影响因子：
64.8
通讯作者：
Guyot-Sionnest, P
中科院分区：
文献类型：
--
作者：
Shim, M;Guyot-Sionnest, P
胶体半导体纳米晶体(1,2)将分子的物理和化学性质与半导体的光电性质结合起来。它们的颜色高度可控，这是电子态量子限制的直接结果(3)。这种纳米晶体是“人造原子”的一种形式（参考文献4），可应用于光电系统，例如发光二极管（5,6）和光伏电池（7），或作为未来纳米电子器件的组件。控制电子占据的能力（特别是在 n 型或 p 型纳米晶体中）对于调整电学和光学特性非常重要，并且应该会带来更广泛的实用器件。但迄今为止，通过引入杂质原子进行的常规掺杂尚未成功：杂质往往会从小晶核中排出（如在磁性杂质（8）中观察到的那样），并且杂质的热电离（提供自由载流子）受到强约束的阻碍。在这里，我们报告了使用导电有机聚合物领域常用的电子转移方法制造 n 型纳米晶体(9)。我们发现以胶体形式制备的半导体纳米晶体可以制成n型，其中电子处于量子限制态。
Colloidal semiconductor nanocrystals(1,2) combine the physical and chemical properties of molecules with the optoelectronic properties of semiconductors. Their colour is highly controllable, a direct consequence of quantum confinement on the electronic states(3). Such nanocrystals are a form of 'artificial atoms' (ref. 4) that may rnd applications in optoelectronic systems such as light-emitting diodes(5,6) and photovoltaic cells(7), or as components of future nanoelectronic devices. The ability to control the electron occupation (especially in n-type or p-type nanocrystals) is important for tailoring the electrical and optical properties, and should lead to a wider range of practical devices. But conventional doping by introducing impurity atoms has been unsuccessful so far: impurities tend to be expelled from the small crystalline cores (as observed for magnetic impurities(8)), and thermal ionization of the impurities (which provides free carriers) is hindered by strong confinement. Here we report the fabrication of n-type nanocrystals using an electron transfer approach commonly employed in the field of conducting organic polymers(9). We find that semiconductor nanocrystals prepared as colloids can be made n-type, with electrons in quantum confined states.