Materials World Network: Collaborative Investigation of Defects in ZnO

宽带隙半导体ZnO由于其在蓝光激光二极管和LED、光探测器、高功率放大器以及化学/气体传感等方面的潜在应用而受到前所未有的关注。然而，进展仍然受到高浓度的点缺陷，表面稳定性问题以及缺乏可靠的p型掺杂的挑战。体缺陷和表面缺陷降低了发射器的效率和激光器的工作寿命，并导致电子器件的早期退化。ZnO的不可再生和不稳定的p型导电性可能与表面导电性的未知缺陷和特性的自补偿有关，这使得ZnO不能用作有效的发射体。与现在可获得的关于ZnO中激子发射的丰富信息相比，只有少量关于表面性质和负责宽发光带的点缺陷的有用且可靠的信息。这项计划拨款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物理技术研究所之间的ZnO缺陷的合作研究的发展。研究人员和他们的学生开发的方法，涉及样品的增长，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，更普遍的是，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.