Bridging the Miscibility Gap in InGaN Alloys

缩小 InGaN 合金的混溶性差距

• 批准号: 0906879
• 负责人: Jingyu Lin
• 金额: $ 47.52万
• 依托单位: Texas Tech University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2013-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0906879&HistoricalAwards=false
• 关键词: Bridging; Miscibility; Gap; InGaN; Alloys

"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)." Technical. This project addresses the epitaxial growth of high crystalline quality InGaN across the complete composition range. The aim is to gain greater understanding of the properties of the miscibility gap and to explore methods that can consistently provide single phase InGaN films. Theoretical studies suggest that phase separation in layers having the interface oriented parallel to the c-axis (such as a- or m-plane InGaN) is dramatically suppressed. Thus, the approach is to develop MOCVD processes for the growth of InGaN epilayers on a-plane through different epilayer templates (AlN, GaN, and InN). Studies to understand fundamental effects of growth orientation and strain on the miscibility gap in InGaN are expected to lead to a new approach for achieving single phase device quality InGaN epilayers. These films will then allow for studies of fundamental optical and transport properties of InGaN in composition ranges which were previously inaccessible. Detailed studies concerning the optical and transport properties of InxGa1-xN in the miscibility gap region (0.45 x 0.75) have not been possible because these InxGa1-xN films generally have been of very low crystalline quality and exhibit weak or negligible photoluminescence. It is anticipated that many of the important physical properties (structural, optical, and electrical) of InxGa1-xN in the miscibility gap region will be characterized through these studies. Non-Technical. The project addresses fundamental research issues in a topical area of electronic/photonic materials science having technological relevance. The realization of device quality InGaN epilayers over a more complete alloy range would yield significant benefits for many III-nitride based optoelectronic devices. The bandgap of InGaN expands from about 0.7 eV to 3.4 eV, which covers the entire solar spectrum. In principle, a multijunction solar cell or photoelectrochemical cell based on multi-layers of InGaN with different In-contents is highly efficient at capturing different wavelengths of the sunlight passing through the cell. InGaN alloys could also be potentially important thermoelectric (TE) materials and may be an attractive alternative to other materials for the development of TE generators that are able to directly convert heat to electricity in new generation automobiles, radioisotope TE generators in spacecraft or cooling modules for enhanced efficiency and lifetime of micro/nano-scale sensor networks. Attainment of high quality InGaN in the previously predicted miscibility gap region would also significantly benefit the development of high efficiency LEDs with wavelengths longer than 550 nm. The successful attainment of highly efficient green/yellow InGaN LEDs would then enable the technology for white LEDs through the R-G-B three color chip integration approach providing highly efficient light sources for general illumination. The bandgap of In-rich InGaN could also be engineered to match the fiber optic communication wavelength around 1.5 um. Postdoctoral and graduate students will be actively involved in a research program that is highly interdisciplinary in nature including state-of-the-art epitaxial research of photonic materials and structures to advanced materials characterization and micro/nano-scale prototype photonic/optoelectronic device research. Undergraduates will also participate in this research using Whitacre Endowment funds. Plans for education and outreach include the development of hands-on activities to be presented to teams of high school teachers and students on 'Nanophotonics' in conjunction with activities conducted by the Center of Engineering Outreach at TTU.

“该裁决是根据2009年《美国复苏与再投资法》（公法111-5）资助的。”技术的。该项目介绍了整个组成范围内高晶质量INGAN的外延生长。目的是对可交解性差距的性质有更深入的了解，并探索可以始终提供单相膜的方法。理论研究表明，具有平行于C轴（例如A-或M-Plane Ingan）的界面方向的层分离。因此，这种方法是开发通过不同的表层模板（ALN，GAN和INN）在A平面上生长的MOCVD过程。预计了解INGAN的可交解性差距的生长取向和压力的基本影响的研究预计将为实现单相设备质量INGAN EPILAYERS提供新的方法。然后，这些薄膜将允许研究Ingan的基本光学和运输特性，这些构成范围以前无法访问。关于这些差距区域中INXGA1-XN的光学和传输特性的详细研究是不可能的（0.45 x 0.75），因为这些INXGA1-XN膜通常具有非常低的结晶质量，并且表现出弱或可忽略不计的光发光。可以预见，通过这些研究，将表征许多在混乱性差距区域中INXGA1-XN的重要物理特性（结构，光学和电气）。非技术。该项目解决了具有技术相关性的电子/光子材料科学主题领域的基本研究问题。在更完整的合金范围内实现设备质量的Ingan Epolayers将为许多基于III-硝酸盐的光电设备带来重大好处。 Ingan的带隙从约0.7 eV扩展到3.4 eV，覆盖了整个太阳谱。原则上，基于INGAN的多层具有不同内部体内的多仪太阳能电池或光电化学电池，在捕获穿过电池的阳光的不同波长方面非常有效。 INGAN合金也可能是重要的热电（TE）材料，并且可能是其他材料的有吸引力的替代品，用于开发TE发电机，这些发电机能够直接将热量转换为新一代汽车中的电力，飞机上的放射性分测机TE发电机或冷却模块，以增强微/Nano/Nano-Scale-Scale-Scale-Scale-Scale-Scale-Scale-Scale-Scale-Scale-Scale-Scale-Scale-Scale-Scale-Scale-Scale-Scale-Scale-Scale-Scale-Scale-Scale-Scale-Scale-Scale-Scale Sensor。在先前预测的差距区域中，获得高质量的INGAN也将显着有益于波长超过550 nm的高效率LED的发展。然后，成功实现了高效的绿色/黄色INGAN LED，将通过R-G-B三色芯片整合方法为白色LED提供技术，从而为一般照明提供了高效的光源。丰富的Ingan的带隙也可以进行设计，以匹配1.5 um左右的光纤通信波长。博士后和研究生将积极参与一项研究计划，该计划在本质上是高度跨学科的研究，包括对光子材料和结构的最新外延研究，用于先进的材料表征以及微/纳米级的原型光子/光子/光电/光电器设备研究。本科生还将使用白色捐赠基金参加这项研究。教育和宣传计划包括开展动手活动，将与TTU工程外展活动中心进行的活动一起向高中教师和学生的“纳米素养”团队提出。