EAGER: Earth Abundant Element Nitride Semiconductors Based on ZnSnN2

技术描述：存在一个与(In，Ga)N族密切相关的鲜为人知的半导体家族，其中III柱元素被由相同数量的锌和IV柱(Si，Ge，Sn)原子组成的有序阳离子亚晶格所取代。虽然已经合成了含硅和含锗的成员，但基于锡的窄禁带成员还没有合成，这限制了这一系列的应用前景，因为它的带隙范围与(In，Ga)N非常相似。本项目致力于高质量氮化锡锌单晶薄膜的生长和表征，以及对其基本光学和电学性质的测定，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、高能衍射以及X射线衍射以及电子和扫描探针显微镜工具来评估结晶度和微观结构；使用由离子束分析校准的能量色散光谱来评估化学计量比。使用光学吸收和光致发光光谱评估光学性能，使用霍尔效应技术测量电学特性。非技术描述：许多替代硅太阳能电池的无机半导体含有铟，这种元素的丰度只是银的三倍，而且需求显著增加。相比之下，II-IV-氮化物系列是由地球上丰富的元素合成的，这些元素已经有了大量的回收基础设施，从经济和环境的角度来看，它对光伏和固态照明等光电子应用都很有价值。高质量的新材料样品也为更广泛的半导体领域提供了重要的机会，以提高我们对薄膜生长过程以及缺陷的性质和作用在决定基本材料性能方面的理解。在半导体合成和表征以及光伏方面对学生进行当代问题的教育，为他们提供与半导体行业和实现下一代设备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职业提供了一条宝贵的途径，同时也让他们深入了解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.