Semiconductor Wafer Reuse by Controlled Fracture to Reduce the Cost of Photovoltaics

PROJECT NUMBER: 76

AUTHOR: Desmond Mills, Metallurgical and Materials Engineering | MENTOR: Corinne Packard, Metallurgical and Materials Engineering

ABSTRACT

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This project focuses on methods to reduce substrate cost which is currently the most expensive component in III-V high efficiency photovoltaics. This was accomplished by developing methods to effectively reuse the substrate for solar cell growth multiple times. The project first focused on analyzing the morphology of fracture surfaces in (100) Germanium (Ge) using rapid quantification of local roughness changes from profilometry data,and attempting to reduce the roughness of the material. Secondly, an analysis of the roughness of controlled fracture spalled release layers introduced in (100) Gallium Arsenide (GaAs) to overcome faceting was conducted. The roughness data from a specific region of interest on a given substrate was obtained by developing an automated MATLAB based script and user interface. This allowed for a better understanding of how substrate roughness impacts future solar cell growth.

VISUAL PRESENTATION

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AUTHOR BIOGRAPHY

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Desmond is an undergraduate research student currently working on his Bachelor’s of Science in Metallurgical and Materials Engineering. His research focus is on scalable methods of producing cost effective III-V high efficiency photovoltaics by reducing substrate cost. By analyzing the morphology of fracture surfaces in (100) Ge and attempting to reduce the roughness of the material, methods of introducing spalling release layers to overcome faceting in (100) GaAs is being explored and developed in his research. This method allows for substrate reuse granting multiple growths of multijunction layers for a single substrate layer. A cost effective III-V device may then have significant competition in terrestrial solar markets providing 40% to 50% efficient solar cells to the residential and commercial solar markets. Desmond is participating in a Research Experience for Undergraduates (REU) in the summer of 2020 at Brown University researching stress analysis of thin film devices and aims to pursue a PhD in Materials Science focused on the efficiency and epitaxy processes of producing photovoltaic devices.

Sponsored by Phillips 66