SGER: New Approach to Revolutionize a Photovoltaic Detector Performance Using Electron Injection-Induced Effects in AlGaN

氮化镓基宽禁带半导体在现代电子学中的重要性日益受到人们的关注。氮化镓的应用除了需要高质量材料的可用性外，还需要对其基本电子特性进行可控的修改。氮化镓基光伏探测器的光谱响应通常受到高能吸收系数大和少数载流子扩散长度小的限制。为了克服这些限制，最近的设计变化包括使用p-i-n代替p-n结[1-4]，用AlxGa1-xN[1-3]或半透明凹窗[2]代替GaN，以及背照光检测器配置[3]。然而，为了提高iii -氮化物器件的性能，对基本（Al）GaN特性的调整从未被直接考虑过。该提案的创新之处是通过调整（Al）GaN中的少数载流子扩散长度来显着提高光伏探测器的性能。扩散长度是决定探测器量子效率和光响应的重要参数。基础概念由PI定义。最近的研究结果[5-8]表明，在固态器件（p-n结或肖特基势垒）中施加外部电压注入p-(Al)GaN会增加临界少数载流子扩散长度和寿命。材料的其他性质，包括发光和光谱光响应也发生了一致的变化，这归因于深亚稳镁受体相关中心[6]的充电。这项研究的实际意义是通过短时间（最多1500秒）电子注入实现（Al） gan基光伏探测器的长期（天），革命性（高达数量级！）性能增强。这是因为扩散长度的增加改善了少数载流子的收集，并消除了载流子在收集前重组的“死区”。拟议的项目是高风险的，因为必须确定p-(Al)GaN[5-8]中的新型电子注入诱导效应是否具有普遍性并代表p型材料的基本特性，或者它们是否取决于材料的质量，生长和加工条件。如果这种效应确实是普遍的，那么通过操纵材料来改变光伏探测器性能的这种新颖而简单的方法的发展将会带来很高的回报。S传输特性，这可能会与设计和技术改进相结合。这种SGER应用的成功将导致这种方法在商业探测器中的实现，并将推进该技术在其他扩散长度至关重要的双极器件（晶体管，晶闸管）中的应用。计划在此项目成功的基础上提交一份GOALI提案（与康宁一起）。这项研究的广泛影响将是对氮化镓和相关化合物中的电子传递的深入理解，研究与教育的结合，以及与工业的合作。

Wide band gap GaN-based semiconductors are attracting increasing attention due to their importance in modern electronics. The applications of GaN necessitate the controlled modification of its fundamental electronic properties, in addition to the availability of high quality material. The spectral response of the GaN-based photovoltaic detectors is generally limited by the large absorption coefficient at high energies and the small minority carrier diffusion length. Recent design changes, to overcome these limitations, include the use of p-i-n instead of p-n junction [1-4], substitution of GaN by AlxGa1-xN [1-3] or semitransparent recessed windows [2], and a back-illuminated detector configuration [3]. However, a tuning of fundamental (Al)GaN properties, to boost the performance of III-Nitride devices, was never directly considered. The innovation in this proposal is to significantly enhance a photovoltaic detector performance by tailoring the minority carrier diffusion length in (Al)GaN. The diffusion length is a crucial parameter for the detector quantum efficiency and photoresponse. The underlying concept is defined by the PI.s recent findings [5-8] that electron injection into p-(Al)GaN from the application of an external voltage in a solid state device--p-n junction or Schottky barrier-increases the critical minority carrier diffusion length and lifetime. Consistent changes were observed in other material properties, including luminescence and spectral photoresponse, and were attributed to charging of deep metastable Mg-acceptor-related centers [6]. The practical significance of this research is a long-term (days), revolutionary (up to an order of magnitude!) performance enhancement for (Al)GaN-based photovoltaic detectors, achieved through short time (at most 1500 sec) electron injection. This is because the increased diffusion length improves minority carrier collection and eliminates the "dead space", where carriers recombine before they are collected. The proposed project is of high risk, since it must be determined whether the novel electron injection-induced effects in p-(Al)GaN [5-8] are universal in nature and represent a fundamental property of the p-type material, or if instead they depend on the material's quality, growth, and processing conditions. If, indeed, the effects are universal, a high pay off will be manifested in a development of this novel and simple approach to revolutionize photovoltaic detector performance by manipulating the material.s transport properties, which will likely be used in combination with design and technology improvements. Success in this SGER application will lead to the implementation of this approach in commercial detectors, and will advance the frontiers of this technology for use in other bipolar devices for which the diffusion length is critical (transistors, thyristors) [6]. It is planned to submit a GOALI proposal (with Corning) based on success of this project. The broader impact of this research will be a dipper understanding of electron transport in GaN and related compounds, the integration of research with education, and partnership with industry.