Materials World Network: Collaborative Investigation of Defects in ZnO

宽禁带半导体氧化锌因其在蓝光激光二极管和发光二极管、光学探测器、大功率放大器和化学/气体传感等方面的潜在应用而受到前所未有的关注。然而，进展仍然受到点缺陷高度集中、表面稳定性问题以及缺乏可靠的p型掺杂的挑战。与体相和表面相关的缺陷降低了发射体的效率，降低了激光器的工作寿命，并导致电子器件提前退化。氧化锌p型电导的不可重复性和不稳定性阻碍了它作为高效发射极的应用，这很可能与未知缺陷和表面电导率的特性的自补偿有关。与目前关于氧化锌中激子发射的丰富信息相比，关于表面性质和导致宽发光带的点缺陷的有用和可靠的信息只有少量。这项计划拨款支持弗吉尼亚联邦大学、德国布伦斯韦格工业大学和俄罗斯IOFE物理技术研究所开展关于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涉及样本生长、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，更广泛地说，他们有在外国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.