Yang Xun, Gan Haibo, Tian Yan, Peng Luxi, Xu Ningsheng, Chen Jun, Chen Huanjun, Deng Shaozhi, Liang Shi-Dong, Liu Fei
State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou, 510275, P. R. China.
Sci Rep. 2017 Oct 12;7(1):13057. doi: 10.1038/s41598-017-12741-5.
There are more or less dopants or defects existing in nanomaterials, so they usually have different conduct-types even for the same substrate. Therefore, fast identification of the conduction-type of nanomaterials is very essential for their practical application in functional nanodevices. Here we use the field emission (FE) technique to research nanomaterials and establish a generalized Schottky-Nordheim (SN) model, in which an important parameter λ (the image potential factor) is first introduced to describe the effective image potential. By regarding λ as the criterion, their energy-band structure can be identified: (a) λ = 1: metal; (b) 0.5 < λ < 1: n-type semiconductor; (c) 0 < λ < 0.5: p-type semiconductor. Moreover, this method can be utilized to qualitatively evaluate the doping-degree for a given semiconductor. We test numerically and experimentally a group of nanomaterial emitters and all results agree with our theoretical results very well, which suggests that our method based on FE measurements should be an ideal and powerful tool to fast ascertain the conduction-type of nanomaterials.
纳米材料中或多或少存在掺杂剂或缺陷，因此即使对于相同的衬底，它们通常也具有不同的导电类型。因此，快速识别纳米材料的导电类型对于其在功能纳米器件中的实际应用至关重要。在此，我们使用场发射（FE）技术研究纳米材料并建立了一个广义的肖特基 - 诺德海姆（SN）模型，其中首次引入了一个重要参数λ（镜像势因子）来描述有效镜像势。通过将λ作为判据，可以识别它们的能带结构：（a）λ = 1：金属；（b）0.5 < λ < 1：n型半导体；（c）0 < λ < 0.5：p型半导体。此外，该方法可用于定性评估给定半导体的掺杂程度。我们对一组纳米材料发射体进行了数值和实验测试，所有结果与我们的理论结果非常吻合，这表明我们基于场发射测量的方法应该是快速确定纳米材料导电类型的理想且强大的工具。
