Flexible GaAs solar cells on roll-to-roll processed epitaxial Ge films on metal foils: a route towards low-cost and high-performance III–V photovoltaics

In this work, we describe a unique roll-to-roll plasma-enhanced chemical vapor deposition (R2R-PECVD) technique to grow high-quality single-crystalline-like Ge films on flexible metal foils, an important advancement towards scalable processing of epitaxial Ge films at low-cost. Ion-beam assisted dep...

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Bibliographic Details
Published in:Energy & environmental science 2019-01, Vol.12 (2)
Main Authors: Dutta, P., Rathi, M., Khatiwada, D., Sun, S., Yao, Y., Yu, B., Reed, S., Kacharia, M., Martinez, J., Litvinchuk, A. P., Pasala, Z., Pouladi, S., Eslami, B., Ryou, J. -H., Ghasemi, H., Ahrenkiel, P., Hubbard, S., Selvamanickam, V.
Format: Article
Language:English
Subjects:
chemistry
energy & fuels
engineering
environmental sciences & ecology
SOLAR ENERGY
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Summary:In this work, we describe a unique roll-to-roll plasma-enhanced chemical vapor deposition (R2R-PECVD) technique to grow high-quality single-crystalline-like Ge films on flexible metal foils, an important advancement towards scalable processing of epitaxial Ge films at low-cost. Ion-beam assisted deposition was used to create single-crystalline-like substrate templates to enable epitaxial growth of Ge films. The Ge films were highly (004) oriented, biaxially-textured and showed remarkable crystalline quality, equivalent to single-crystal Ge wafers. Subsequently, the Ge films on metal foils were used as substrates to fabricate flexible GaAs single-junction solar cell by metal-oxide chemical vapor deposition (MOCVD). The champion device showed efficiency of 11.5%, and the average efficiency of four devices was 8% at 1 sun, the highest reported on GaAs PV directly deposited on alternative flexible substrates. Devices made on CVD-Ge film exhibited significantly improved performance compared to the ones grown on sputtered Ge films. Scalable production of inexpensive and flexible epi-Ge films will not only be useful for developing low-cost and high-performance III–V solar cells, but also for emerging flexible electronic devices applications.
ISSN:1754-5692