Shao Rui-wen, Zheng Kun, Wei Bin, Zhang Yue-fei, Li Yu-jie, Han Xiao-dong, Zhang Ze, Zou Jin
Institute of Microstructure and Properties of Advanced Materials, Beijing University of Technology, Beijing 100124, China.
Nanoscale. 2014 May 7;6(9):4936-41. doi: 10.1039/c4nr00059e.
Bandgap engineering is a common practice for tuning semiconductors for desired physical properties. Although possible strain effects in semiconductors have been investigated for over a half-century, a profound understanding of their influence on energy bands, especially for large elastic strain remains unclear. In this study, a systematic investigation of the transport properties of n-type [0001] ZnO nanowires was performed at room temperature using the in situ scanning tunnelling microscope-transmission electron microscope technique which shows that the transport properties vary with the applied external uniaxial strain. It has been found that the resistance of ZnO nanowires decreases continuously with increasing compressive strain, but increases under increased tensile strain, suggesting piezo-resistive characteristics. A series of near-band-edge emissions were measured and the corresponding variations of bandgaps were obtained during the application of tensile strain of individual ZnO nanowires via cathodoluminescence spectroscopy. From this, a relationship between the changes of energy bandgap and the transport properties, both induced by uniaxial strain, is built.
带隙工程是一种通过调整半导体以获得所需物理特性的常见做法。尽管对半导体中可能存在的应变效应已经研究了半个多世纪，但对于它们对能带的影响，尤其是对大弹性应变的影响，仍缺乏深入的了解。在本研究中，利用原位扫描隧道显微镜-透射电子显微镜技术在室温下对n型[0001] ZnO纳米线的输运性质进行了系统研究，结果表明输运性质随施加的外部单轴应变而变化。研究发现，ZnO纳米线的电阻随压缩应变的增加而持续降低，但在拉伸应变增加时则增大，表明具有压阻特性。通过阴极发光光谱法测量了一系列近带边发射，并在对单个ZnO纳米线施加拉伸应变的过程中获得了相应的带隙变化。由此，建立了由单轴应变引起的能带隙变化与输运性质之间的关系。
