Lu Shengnan, Qi Junjie, Gu Yousong, Liu Shuo, Xu Qiankun, Wang Zengze, Liang Qijie, Zhang Yue
State Key Laboratory for Advanced Metals and Materials, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, People's Republic of China.
Nanoscale. 2015 Mar 14;7(10):4461-7. doi: 10.1039/c4nr07619b.
The piezotronic effect, which utilizes the piezopotential to engineer the interface characteristics, has been widely exploited to design novel functional device or to optimize the device performance, which is intimately related to the carrier concentration. Here, by constructing a general Schottky diode, the piezotronic effect dependence on the carrier concentration was investigated systematically using ultraviolet (UV) illumination. Scanning Kelvin Probe Microscopy was employed to quantify the carrier concentration in ZnO nanorods under UV illumination. The results showed that the carrier concentration increases with increasing light intensity and an average value of up to 5.6 × 10(18) cm(-3) under 1.2 mW cm(-2) light illumination was obtained. Furthermore, with increasing UV light intensity, an increasingly imperceptible variation in the current-voltage characteristics under strain was observed, which finally disappeared under 1.2 mW cm(-2) light illumination. This phenomenon was attributed to the weakened modulation ability of the piezopotential due to the strengthened screening effect. In addition, the gradual disappearing in the barrier also contributed to the gradual disappearance of the piezotronic effect. This study provides an in-depth understanding of piezotronics, which could be extended to other piezoelectric devices and guide the design and optimization of piezotronic and even piezophototronic devices.
利用压电势来调控界面特性的压电电子效应，已被广泛用于设计新型功能器件或优化器件性能，这与载流子浓度密切相关。在此，通过构建一个普通的肖特基二极管，利用紫外（UV）光照系统地研究了压电电子效应与载流子浓度的关系。采用扫描开尔文探针显微镜来量化紫外光照下ZnO纳米棒中的载流子浓度。结果表明，载流子浓度随光强增加而增大，在1.2 mW/cm²光照下获得的平均值高达5.6×10¹⁸ cm⁻³。此外，随着紫外光强增加，观察到应变下电流-电压特性的变化越来越不明显，最终在1.2 mW/cm²光照下消失。这种现象归因于由于屏蔽效应增强导致压电势的调制能力减弱。此外，势垒的逐渐消失也导致了压电电子效应的逐渐消失。本研究为压电电子学提供了深入理解，可扩展到其他压电器件，并指导压电电子甚至压电光电器件的设计和优化。
