Studies of the Electron Injection-Induced Effects in III-Nitride Device Structures

该项目的出发点是PI最近的发现，即电子注入p型GaN会导致材料的电子特性发生相当大的变化，特别是少数载流子扩散长度更长。这个为期三年的项目的智力价值是在探索新的电子注入诱导效应在广泛的p型Mg掺杂的AlxGa 1-xN（x 0.35）和AlxGa 1-xN/GaN超晶格。此外，在掺杂有除Mg以外的杂质（例如锰或铁）的III族氮化物和III-N合金以及除AlxGa 1-xN和 AlxGa 1-xN/GaN（例如InxGa 1-xN和InxGa 1-xN/GaN）将被研究。为了充分理解新的电子注入诱导效应，并实现对器件性能的控制，将在三族氮化物基结构的代表性范围内进行系统的电学和光学研究。在电子注入之前和之后将进行电气测量，包括深能级瞬态谱和电子束感应电流。这些测量将与阴极射线发光，光响应，以及光电导测量能够提供光学和光电性能的关键信息的补充。该项目的更广泛的影响是在研究生和本科生水平的研究和教育的整合，以及与行业（SVT协会）的伙伴关系。该项目更广泛影响的另外两个方面是女博士的参与。学生和本科生从历史上黑色（白求恩-库克曼）学院在拟议的研究。最后，该项目的国际层面是在PI与德国慕尼黑技术大学沃尔特·肖特基研究所的一个小组的密切合作下进行的。 这项研究的实际意义在于长期的，几倍的提高三族氮化物紫外探测器的量子效率。这是因为增加的扩散长度改善了少数载流子收集，并消除了载流子在被收集之前重新结合的“死区”。

The starting point of this project is the PI's recent findings that electron injection into p-type GaN leads to considerable changes in the material's electronic properties, in particular longer minority carrier diffusion length. The intellectual merit of this three-year project is in exploration of the novel electron injection-induced effects in the wide range of p-type Mg-doped AlxGa1-xN (x 0.35) and AlxGa1-xN/GaN superlattices. In addition, the electron injection effects in III-Nitrides doped with impurities other than Mg (manganese or iron, for example) and III-N alloys and superlattices other than AlxGa1-xN and AlxGa1-xN/GaN (InxGa1-xN and InxGa1-xN/GaN, for example) will be studied. To fully understand the novel electron injection-induced effects and to achieve control over device performance, systematic electrical and optical studies will be carried out in the representative range of III-Nitride-based structures. Electrical measurements, which include Deep Level Transient Spectroscopy and Electron Beam Induced Current, will be performed before and after electron injection. These measurements will be complemented with cathodoluminescence, photoresponse, as well as photoconductivity measurements able to provide critical information on optical and optoelectronic properties. The broader impact of this project is in integration of research and education at the graduate and undergraduate levels as well as in partnership with industry (SVT Associates). Two other aspects of the project's broader impact are in participation of a female Ph.D. student and undergraduates from a Historically Black (Bethune-Cookman) College in the proposed research. Finally, the international dimension of the project is in close collaboration of the PI with a group at the Walter Schottky Institute of Munich Technical University in Germany. The practical significance of this research is in long-term, several-fold enhancement of quantum efficiency for III-Nitride ultra-violet detectors. This is because the increased diffusion length improves minority carrier collection and eliminates the "dead space" where carriers recombine before they are collected.