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Mechanically tunable conductivity in piezoelectric semiconductors

压电半导体中的机械可调电导率

基本信息

批准号：
317658731
负责人：
Professor Dr. Hans-Joachim Kleebe
金额：
--
依托单位：
Institut für Angewandte Geowissenschaften (IAG)
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2016
资助国家：
德国
起止时间：
2015-12-31 至 2020-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/317658731?language=en
关键词：
Mechanically tunable conductivity piezoelectric semiconductors

项目摘要

The unique electrical properties in varistors and diodes rely on doping and interfacial potential barriers which are permanently implemented into the device. Here we provide a fundamentally new approach, geared towards piezoelectric semiconductors in which an interfacial electrostatic potential barrier can be reversibly tuned through external mechanical stress. The concept is related to piezotronics that so far has been focused, however, on Schottky barriers in nanofibers and yielded only small changes of potential barrier heights.This novel concept is fundamentally investigated using ZnO as semiconductor with high piezoelectric coefficient. The focus will be on single (ZnO/metal) and double (ZnO/ZnO) Schottky barriers with well determined orientations utilizing ZnO single crystals. Tailoring is then afforded using grain conductivity of the ZnO, work function of the metal and interface states determined by grain boundary misorientation and interface dopants. The additional flexibility arises due to the application of interfacial stresses during electric loading. Electrical characterisations in collaboration with other projects will be on density of electron states and electron mobility, in terms of impedance spectroscopy and I V curves at different frequency and temperature. A special challenge lies in the dichotomy of stress-tuned interfacial charge and semiconductor conductivity-enticed charge screening. At the same time, this project will provide polycrystalline ZnO to aid validation of modelling projects and affords electromechanical characterisation of polarisation texture of ZnO.

压敏电阻和二极管的独特电气特性依赖于永久性地实现到器件中的掺杂和界面势垒。在这里，我们提供了一种全新的方法，面向压电半导体，其中界面静电势垒可以通过外部机械应力可逆地调整。这一概念与压电电子学有关，但是，迄今为止一直集中在纳米纤维中的肖特基势垒上，并且只产生势垒高度的微小变化。重点将是单（ZnO/金属）和双（ZnO/ZnO）肖特基势垒，以及确定的方向，利用ZnO单晶。然后，提供定制使用晶粒的ZnO的导电性，金属的功函数和界面状态确定的晶界取向差和界面掺杂剂。由于在电加载期间施加界面应力而产生额外的柔性。与其他项目合作的电气表征将针对电子态密度和电子迁移率，即不同频率和温度下的阻抗谱和IV曲线。一个特殊的挑战在于应力调谐界面电荷和半导体电导诱导电荷屏蔽的二分法。同时，该项目将提供多晶ZnO，以帮助验证建模项目，并提供ZnO极化纹理的机电特性。