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. Issue 2 (30th January 2019)

• Record Type: Journal Article
• 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.
• Is Part Of: Energy & environmental science. Volume 12:Issue 2(2019)
• Page Start: 756
• Page End: 766
• Publication Date: 2019-01-30
• Subjects: Energy conversion -- Periodicals; Fuel switching -- Periodicals; Environmental sciences -- Periodicals; Environmental chemistry -- Periodicals; 333.79
• DOI: 10.1039/c8ee02553c
• Languages: English
• ISSNs: 1754-5692

Abstract

Abstract : Single-junction GaAs solar cells were developed on metal foils, laying the foundation for scalable manufacturing of low-cost, lightweight and high-efficiency flexible III–V solar cells. Abstract : In this report, 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.