Piezotronic effect at Schottky barrier of a metal-ZnO single crystal interface
Piezotronic effect at Schottky barrier of a metal-ZnO single crystal interface
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DOI：
10.1063/1.4981243
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发表时间：
2017-04-21
影响因子：
3.2
通讯作者：
Novak, Nikola
中科院分区：
文献类型：
--
作者：
Keil, Peter;Froemling, Till;Novak, Nikola
基于压电效应，ZnO被认为是未来应用最有前途的半导体材料之一。对ZnO纳米线进行了深入的研究，以了解压电对金属ZnO界面处肖特基势垒高度的调制。然而，对ZnO单晶体的实验研究以及理论和实验确定的势垒高度变化的基本比较仍然缺乏。因此，利用O端和zn端表面，由于应力诱导的压电电荷，对金属- zno单晶界面上的静电势垒高度进行了调整。利用地应力相关的阻抗和电流-电压测量来提取势垒的电学特性，并确定势垒高度的降低。界面电阻的减小和电容的增大表明应力压电电荷的存在。实验结果表明，在70兆帕下，势垒高度的变化约为9 meV，这支持了先前对金属- zno纳米线的研究。如果假设界面层厚度近似于2埃，这种变化与基于不完全筛分模型的理论计算结果很好地吻合。AIP出版社出版。
ZnO is considered as one of the most promising semiconductor materials for future applications based on the piezotronic effect. Intense studies on ZnO nanowires had been carried out to understand the modulation of the Schottky barrier height at the metal ZnO interface via piezoelectricity. However, an experimental investigation on bulk ZnO single crystals and a fundamental comparison of the modification of the barrier height determined experimentally and theoretically are still missing. Therefore, an adjustment of the electrostatic potential barrier height at metal-ZnO single crystal interfaces due to stress induced piezoelectric charges was conducted, using both O- and Zn-terminated surfaces. In-situ stress dependent impedance and current-voltage measurements were utilized to extract the electrical properties of the potential barrier and to determine the reduction of the barrier height. The decrease of the interface resistance and increase of the capacitance reveal the presence of stress induced piezoelectric charges. The experimentally evaluated reduction of the barrier height reveals a moderate change of about 9 meV at 70 MPa and supports prior work on metal-ZnO nanowires. This change was found to be in good agreement with theoretical calculations based on the imperfect screening model if a thickness of the interface layer is assumed to be similar to 2 angstrom. Published by AIP Publishing.