RUI: Fundamental Studies of a-Ge:H and a-SiGe:H Deposition by Reactive Magnetron Sputtering

技术说明：本项目旨在更好地了解与光伏应用相关的直流反应磁控溅射材料沉积氢化非晶锗(a-Ge：H)和氢化非晶硅锗(a-SiGe：H)的过程。该方法的重点是在生长过程中进入表面的能量和动量通量在决定薄膜性能方面的作用，以及阐明氢在薄膜中的结合机制。等离子体密度将使用不平衡的磁控管和外部磁场来系统地改变；射频偏置将用于控制离子能量。等离子体特性将使用等离子体探头来确定。溅射原子输运的蒙特卡罗模拟将被用来确定高能中性轰击的能量、通量和角分布，并通过沉积剖面的实验研究来验证。氢的掺入动力学将通过质谱学和光学发射光谱进行研究。这些数据将与所得薄膜的成分、结构、光学和电学性质相关联，这些性质由光学传输和反射光谱、红外吸收光谱、卢瑟福背散射、弹性反冲探测、光和暗电导以及亚能隙吸收光谱确定。这些信息将为理解这些材料与氢化非晶硅相比性能较差的原因提供可靠的基础，并应导致这些具有重要技术意义的材料的进一步优化。这项研究可望为我们对溅射沉积薄膜生长的基本认识做出重要贡献。非技术解释该项目涉及与电子和光子学有很强技术相关性的基础材料研究，并有效地将研究和教育结合在一起。这项研究将与Macalester学院的本科生研究助理合作进行，Macalester学院是一所四年制文科学院。该项目将为学生提供独特的研究机会，为学年的独立研究项目提供选择，并在物理课程中加强与材料科学有关的课程，从而为学生提供宝贵的研究培训。它还将作为本科院校材料研究的典范，以及文理学院物理系研究与教学相结合的典范。

TECHNICAL EXPLANATION: This project aims for greater understanding of the deposition of hydrogenated amorphous germanium (a-Ge:H) and hydrogenated amorphous silicon-germanium (a-SiGe:H) by direct current reactive magnetron sputtering-materials with relevance to photovoltaic applications. The approach focuses on the role of energy and momentum flux into the surface during growth in determining film properties, and the elucidation of the mechanism of hydrogen incorporation in the film. The plasma density will be systematically varied using an unbalanced magnetron and an external magnetic field; a radio frequency bias will be used to control the ion energy. Plasma characteristics will be determined using plasma probes. Monte Carlo simulations of sputter atom transport will be utilized to determine the energy, flux, and angular distribution of energetic neutral bombardment, to be verified by experimental studies of deposition profiles. Hydrogen incorporation kinetics will be studied by mass spectrometry and optical emission spectroscopy. These data will be correlated with compositional, structural, optical, and electrical properties of the resulting films as determined by optical transmission and reflection spectroscopy, infrared absorption spectroscopy, Rutherford Back Scattering, Elastic Recoil Detection, photo and dark conductivity, and subgap absorption spectroscopy. This information will provide a sound basis for understanding the causes of the inferior properties of these materials compared to hydrogenated amorphous silicon, and should lead to further optimization of these technologically important materials. This study is expected to make an important contribution to basic understanding of thin film growth by sputter deposition.. NON-TECHNICAL EXPLANATIONThe project addresses fundamental materials research with strong technological relevance to electronics and photonics, and effectively integrates research and education. The research will be carried out in collaboration with undergraduate research assistants at Macalester College, a four-year liberal arts college. The project will provide valuable research training for students by providing unique research opportunities, by providing options for academic year independent research projects, and by enhancing courses related to materials science in the physics curriculum. It will also serve as a model for materials research at an undergraduate institution, and as a model for the integration of research and teaching in a liberal arts college physics department.