Materials World Network: Collaborative Investigation of Defects in ZnO

宽禁带半导体ZnO由于其在蓝色激光二极管和led、光学探测器、大功率放大器和化学/气体传感方面的潜在应用而受到前所未有的关注。然而，由于点缺陷的高度集中，表面稳定性问题以及缺乏可靠的p型掺杂，进展仍然受到挑战。体积和表面缺陷降低了发射器的效率，降低了激光器的工作寿命，并导致电子器件的早期退化。ZnO的p型电导率不稳定且不可复制，这可能与表面电导率未知缺陷和特性的自补偿有关，从而阻碍了其作为高效发射极的使用。与现有的大量关于ZnO激子发射的信息相比，关于ZnO表面特性和导致宽发光带的点缺陷的有用和可靠的信息很少。该计划资助支持弗吉尼亚联邦大学、德国布伦瑞克技术大学和俄罗斯Ioffe物理技术研究所对氧化锌缺陷的合作研究。研究人员和他们的学生开发的方法包括样品生长、表征和建模，以及活动之间的反馈。美国研究生学习样品生长和制备技术，更一般地说，在国外研究实验室工作的经验。

The wide-bandgap semiconductor ZnO has gained unprecedented attention due to its potential applications in blue laser diodes and LEDs, optical detectors, high-power amplifiers, and chemical/gas sensing. Progress, however, is still challenged by the high concentration of point defects, problems with stability of the surface, and the lack of reliable p-type doping. The bulk and surface-related defects reduce efficiency of emitters, laser operation lifetimes, and lead to earlier degradation of electronic devices. It is likely that the irreproducible and unstable p-type conductivity of ZnO, which precludes its use as an efficient emitter, is related to self-compensation with unknown defects and peculiarities of the surface conductivity. Compared to the wealth of information now available on exciton emission in ZnO, there is only a small amount of useful and reliable information on surface properties and on point defects responsible for broad luminescence bands. This planning grant supports the development of a collaborative study of defects in ZnO between Virginia Commonwealth University, the Technical University of Braunschweig, Germany, and the Ioffe Physico-Technical Institute, Russia. The investigators and their students develop approaches that involves sample growth, characterization, and modeling, as well as feedback between the activities. US graduate students learn sample growth and preparation techniques and, more generally, experience working at the foreign research laboratories.