Cooke Jacqueline, Ranga Praneeth, Jesenovec Jani, McCloy John S, Krishnamoorthy Sriram, Scarpulla Michael A, Sensale-Rodriguez Berardi
Department of Electrical and Computer Engineering, The University of Utah, Salt Lake City, UT, 84112, USA.
Institute of Materials Research, Washington State University, Pullman, WA, 99164-2920, USA.
Sci Rep. 2022 Feb 25;12(1):3243. doi: 10.1038/s41598-022-07242-z.
In this work, a systematic photoluminescence (PL) study on three series of gallium oxide/aluminum gallium oxide films and bulk single crystals is performed including comparing doping, epitaxial substrates, and aluminum concentration. It is observed that blue/green emission intensity strongly correlates with extended structural defects rather than the point defects frequently assumed. Bulk crystals or Si-doped films homoepitaxially grown on (010) β-GaO yield an intense dominant UV emission, while samples with extended structural defects, such as gallium oxide films grown on either (-201) β-GaO or sapphire, as well as thick aluminum gallium oxide films grown on either (010) β-GaO or sapphire, all show a very broad PL spectrum with intense dominant blue/green emission. PL differences between samples and the possible causes of these differences are analyzed. This work expands previous reports that have so far attributed blue and green emissions to point defects and shows that in the case of thin films, extended defects might have a prominent role in emission properties.
在这项工作中，对三个系列的氧化镓/铝镓氧化物薄膜和块状单晶进行了系统的光致发光（PL）研究，包括比较掺杂、外延衬底和铝浓度。观察到蓝/绿发射强度与扩展结构缺陷密切相关，而不是与通常假定的点缺陷相关。在（010）β-GaO上同质外延生长的块状晶体或硅掺杂薄膜产生强烈的主导紫外发射，而具有扩展结构缺陷的样品，如在（-201）β-GaO或蓝宝石上生长的氧化镓薄膜，以及在（010）β-GaO或蓝宝石上生长的厚铝镓氧化物薄膜，都显示出非常宽的PL光谱，且以强烈的主导蓝/绿发射为主。分析了样品之间的PL差异以及这些差异的可能原因。这项工作扩展了以前将蓝绿色发射归因于点缺陷的报道，并表明在薄膜的情况下，扩展缺陷可能在发射特性中起重要作用。
