Thin film III-V photovoltaics (PV) are a high efficiency, low weight alternative to silicon. However, high costs make practical use cases limited to weight specific applications. These high costs are largely contained in material costs and especially thick substrates used as seed and handle layers for devices grown atop them. Removal and reuse of the substrates post device growth leads to a significant reduction in the material cost to make these devices. Acoustic assisted spalling (Sonic Wafering) is a low-cost substrate removal method that has the potential to significantly reduce costs related to the fabrication of III-V PVs. This thesis outlines design considerations and material characterization comparison of III-V devices made conventionally without substrate removal with those made using acoustic assisted spalling. The viability of SiOx nanoparticles as a release assist layer is also investigated. This investigation was in collaboration with researchers at Arizona State University (ASU), researchers at the National Renewable Energy Laboratory (NREL), and in conjunction with Crystal Sonic, all sponsored by the DOE under grant number DE-FOA-0002064. 3-4% surface coverage of nanoparticles prior to test structure overgrowth leads to small decreases in photoluminescence (80% of control) whereas 30% surface coverage drastically decreases photoluminescence (<0.1% of control). GaAs solar cells removed from their substrates using this acoustic assisted spalling method have measured similar Light IV characteristics (<0.5% efficiency standard deviation) and quantum efficiency (2% integrated Jsc standard deviation) to their non-spalled counterparts.
Department, Program, or Center
School of Physics and Astronomy (COS)
Smith, David, "Effect of Nanoparticle and Acoustic Assisted Spalling on III-V Thin Film Photovoltaic Device Characteristics" (2021). Thesis. Rochester Institute of Technology. Accessed from
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