Dual-Plasma Co-Deposition of Mixed Phase Thin Film Materials

技术：本项目研究非晶/纳米晶（a/nc-Si:H）混合相薄膜的生长和表征。该方法利用双等离子体共沉积工艺，在上游流过管反应器中产生一种纳米晶体颗粒，然后将其注入另一个电容耦合等离子体沉积系统，在该系统中生长周围的半导体或绝缘材料。为了实现用于光伏和电子应用的a/nc-Si:H薄膜的性能，将研究先前工作基础上的材料科学问题，这些问题表明纳米晶夹杂物的临界浓度会导致a/nc-Si:H薄膜中的缺陷密度降低。混合相a/nc-Si:H将通过低温退火或场辅助结晶作为沉积后形成微晶硅薄膜的潜在“种子材料”进行研究。能够单独控制硅纳米晶体和周围的a- si:H的性质，可以合成电子质量较差的多孔a/nc-Si:H薄膜，但具有潜在的高氢扩散系数，可以作为储氢材料。非技术性：项目涉及电子/光子材料科学领域的基础研究问题，具有较高的技术相关性。研究和教育活动将与研究生和本科生在研究计划中的参与相结合。该项目还涉及正式和非正式的科学教育以及代表性不足群体的融合。该项目参与了威斯康辛州梅门尼民族原住民学院（native american College of Menomenie Nation）的工程学士学位预科项目，并将接待来自梅门尼民族部落的高中生和本科生进行暑期研究。外联活动包括与明尼苏达科学博物馆合作，开发向广大公众解释纳米技术前景和挑战的展品。他还是一本科普书（《超级英雄的物理学》）的作者，并经常给公众做讲座。

Technical: This project addresses growth and characterization of amorphous/nanocrystalline (a/nc-Si:H) mixed-phase thin films. The approach utilizes a dual-plasma co-deposition process which produces one type of nanocrystalline particles in an upstream flow-through tube reactor, which are then injected into a second, capacitively-coupled plasma deposition system in which the surrounding semiconductor or insulating material is grown. In order to achieve a/nc-Si:H film properties for photovoltaic and electronic applications, materials science issues underlying previous work showing that a critical concentration of nanocrystalline inclusions leads to lower defect densities in the a/nc-Si:H film will be investigated. The mixed phase a/nc-Si:H will be studied as a potential "seed material" for post-deposition formation of microcrystalline silicon thin films, by either low-temperature annealing or field-assisted crystallization. The ability to separately control the properties of the silicon nanocrystals and the surrounding a-Si:H enables synthesis of porous a/nc-Si:H films of poor electronic quality, but with potentially high hydrogen diffusion coefficients that may serve as hydrogen storage materials.Non-technical: The project addresses basic research issues in a topical area of electronic/photonic materials science with high technological relevance. Research and educational activities will be integrated with involvement of both graduate and undergraduates in the research program. The project also addresses formal and informal science education and integration of underrepresented groups. The PI participates in a program to develop a pre-baccalaureate program in Engineering at the Native-American College of Menomenie Nation in Wisconsin, and will host summer research high school and undergraduate students from the Menomenie Nation tribe. Outreach activities include collaboration with the Science Museum of Minnesota on the development of exhibits explaining the prospects and challenges of nanotechnology to a broad public. The PI is also the author of a popular science book (The Physics of Superheroes) and frequently gives lectures to the general public.