High‐efficiency single‐junction p‐i‐n GaAs solar cell on roll‐to‐roll epi‐ready flexible metal foils for low‐cost photovoltaics. (23rd July 2020)

• Record Type: Journal Article
• Authors: Khatiwada, Devendra; Favela, Carlos A.; Sun, Sicong; Zhang, Chuanze; Sharma, Sahil; Rathi, Monika; Dutta, Pavel; Galstyan, Eduard; Belianinov, Alex; Ievlev, Anton V.; Pouladi, Sara; Fedorenko, Anastasiia; Ryou, Jae‐Hyun; Hubbard, Seth; Selvamanickam, Venkat
• Is Part Of: Progress in photovoltaics. Volume 28:Number 11(2020)
• Page Start: 1107
• Page End: 1119
• Publication Date: 2020-07-23
• Subjects: efficiency -- flexible -- GaAs -- HIM -- MOCVD -- roll‐to‐roll; Solar cells -- Periodicals; Photovoltaic cells -- Periodicals; Solar power plants -- Periodicals; 621.31245
• DOI: 10.1002/pip.3308
• Languages: English
• ISSNs: 1062-7995

Abstract

Abstract: We demonstrate the fabrication and characterization of high‐efficiency, single‐junction p‐i‐n GaAs solar cells, on flexible metal foil with epi‐ready buffer via roll‐to‐roll fabrication. Single‐junction p‐i‐n GaAs solar cells were fabricated using metal–organic chemical vapor deposition (MOCVD). An efficiency greater than 13% was obtained at 1 sun, which is the highest reported efficiency on GaAs photovoltaics directly deposited on metal tapes. This exceeds our previously reported study showcasing 11.5% efficiency on single‐junction p‐n solar cell structure. Improved morphology of p‐i‐n structure compared with p‐n is explained by atomic force microscopy (AFM), scanning electron microscopy (SEM), and helium ion microscopy (HIM) measurements. Time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS) analysis showed reduced Zn diffusion in p‐i‐n cell compared with the p‐n cell. We attribute the improvement in efficiency of p‐i‐n cells on flexible metal tapes to the quality of the junction, surface morphology, controlled diffusion of species within the active layers, and increase in absorption due to the optimized intrinsic layer thickness. Abstract : High‐efficiency single‐junction p‐i‐n GaAs solar cell with different intrinsic layer thickness on roll to roll epi‐ready flexible metal tape was grown, fabricated, and optimized. The bulk/surface morphology and efficiency of single‐junction p‐i‐n solar cells was highly improved on flexible epi‐ready metal foil than its p‐n counterpart. Efficiency greater than 13% has been demonstrated for single‐junction flexible p‐i‐n GaAs solar cells with intrinsic layer thickness of 1000 nm.