EAGER: Earth Abundant Element Nitride Semiconductors Based on ZnSnN2

技术描述：存在一个鲜为人知的半导体族，与（In,Ga）N族密切相关，其中列III元素被由相同数量的Zn和列IV （Si, Ge, Sn）原子组成的有序阳离子亚晶格取代。虽然已经合成了含Si和含ge的成员，但基于Sn的窄带隙成员——实现光谱可见波长部分光子吸收和发射的关键——尚未合成，限制了该家族的应用前景，其带隙范围与（in,Ga）N非常相似。这个项目的重点是高质量锌锡氮化单晶薄膜的生长和表征，并确定其基本的光学和电学性质，特别是关于缺陷和无序的影响。薄膜是用等离子体辅助分子束外延技术生长的。使用原位反射高能衍射、x射线衍射以及电子和扫描探针显微镜工具评估结晶度和微观结构；化学计量学使用离子束分析校准的能量色散光谱进行评估。利用光吸收和光致发光光谱技术评估光学特性，利用霍尔效应技术测量电学特性。非技术描述：许多硅太阳能电池的无机半导体替代品都含有铟，这种元素的含量仅是银的三倍，是一种需求显著增长的商品。相比之下，ii - iv -氮化物家族是由地球上丰富的元素合成的，这些元素已经存在重要的回收基础设施，从经济和环境的角度来看，它对光电应用（如光伏和固态照明）都很感兴趣。新材料的高质量样品也为更广泛的半导体界提供了重要的机会，以提高我们对薄膜生长过程的理解，以及缺陷在决定基本材料特性中的性质和作用。教育学生在半导体合成和表征以及光伏方面的当代问题，为他们提供与半导体行业和下一代器件实现高度相关的重要技能。让高中生接触基本的太阳能电池制造为鼓励他们考虑从事科学和工程方面的职业提供了一条宝贵的途径，同时也让他们了解到当前光伏技术的局限性。

Technical Description: There exists a poorly understood semiconductor family closely related to the (In,Ga)N family where the column III element is replaced by an ordered cation sublattice composed of equal numbers of Zn and column IV (Si, Ge, Sn) atoms. While the Si- and Ge-containing members have been synthesized, the narrow band-gap member based on Sn -- key to realizing photon absorption and emission in the visible wavelength portion of the spectrum -- has not, limiting the application prospects of this family whose band-gap range is very similar to that of (In,Ga)N. This project is focused on growth and characterization of high-quality single-crystal thin films of zinc tin nitride and the determination of its fundamental optical and electrical properties, particularly with respect to the influence of defects and disorder. Thin films are grown using a plasma-assisted molecular beam epitaxy technique. Crystallinity and microstructure are evaluated using in-situ reflection high energy diffraction as well as x-ray diffraction and both electron and scanning probe microscopy tools; stoichiometry is evaluated using energy dispersive spectrometry calibrated using ion beam analysis. Optical properties are evaluated using optical absorption and photoluminescence spectroscopy, and electrical characteristics are measured using Hall effect techniques.Non-technical Description: Many inorganic semiconductor alternatives to silicon solar cells contain indium, an element only three times more abundant than silver and a commodity experiencing significant increases in demand. The II-IV-nitride family in contrast is synthesized from earth-abundant elements for which there already exists significant recycling infrastructure, making it of interest both from economic and environmental perspectives for optoelectronic applications such as photovoltaics and solid state lighting. High-quality samples of new materials also provide important opportunities in the broader semiconductor community to improve our understanding of thin film growth processes, and the nature and role of defects in determining fundamental material properties. Educating students in contemporary issues in semiconductor synthesis and characterization, as well as photovoltaics, provides them with important skills highly relevant to the semiconductor industry and the realization of next-generation devices. Exposing high school students to basic solar cell fabrication provides a valuable pathway to encouraging them to consider careers in science and engineering, while at the same time providing them insight into limitations of current photovoltaic technology.