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

University Of Minnesota-Twin Cities, Minneapolis MN

Investigators

Abstract

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.