Strain dependence of electronic transport in semiconducting oxide thin films

该项目旨在揭示透明导电氧化物多晶薄膜中电子传输的应变相关性。这将使用磁控溅射在柔性硅和玻璃衬底上制备的氧化锌和二氧化锡薄膜来研究。电学特性将通过电导率和霍尔效应测量作为应变的函数来执行。将特别注意晶界的影响。通过对不同载流子浓度样品的随温度变化的霍尔效应测量，我们将阐明限制电子传输的晶界势垒的电子结构是如何被应变改变的。通过比较不同织构的氧化锌薄膜和比较氧化锌和二氧化锡薄膜，可以确定压电性对晶界势垒的贡献。我们还将利用电学技术和光电子能谱来研究氧化锌肖特基势垒的压电改性。该项目与K.Albe的计算氧化锌晶界电子结构的项目密切相关，与J.Rödel和H.-J.Kleebe的项目密切相关，其中J.Rödel和H.-J.Kleebe的项目研究了多晶氧化锌中晶界的机械调制，E.Gjonaj和B.-X.Xu的项目研究了多晶氧化锌中力和电场的耦合及其对电荷输运的影响，J.J.Schneider的项目研究了极化织构的氧化锌陶瓷的合成和性质。

The project aims at unravelling the strain dependence of electron transport in polycrystalline thin films of transparent conductive oxides. This will be studied using thin ZnO and SnO2 films prepared by magnetron sputtering on flexible silicon and glass substrates. The electrical characterisation will be performed as a function of strain by conductivity and Hall effect measurements. Particular attention will be paid to the influence of grain boundaries. How the electronic structure of the grain boundary barrier, which limits electron transport, is modified by strain will be elucidated using temperature dependent Hall effect measurements of samples with variable carrier concentration. The piezoelectric contributions to the grain boundary barriers will be identified by comparing differently textured ZnO films and by comparing ZnO and SnO2 films. Piezoelectric modifications of ZnO Schottky barriers will also be studied using electrical techniques and photoelectron spectroscopy. The project is closely linked to a project of K. Albe in which the electronic structure of ZnO grain boundaries will be calculated, a project of J. Rödel and H.-J. Kleebe in which the mechanical modulation of grain boundaries in ZnO bi- and polycrystals is studied, a project of E. Gjonaj and B.-X. Xu in which the coupling of mechanical and electric fields and their influence on charge transport in polycrystalline ZnO is investigated and a project of J.J. Schneider in which the synthesis and the properties of polarization textured ZnO ceramics are studied.