Ultra-high Photovoltage (2.45 V) Forming in Graphene Heterojunction via Quasi-Fermi Level Splitting Enhanced Effect

• Published in: iScience 2020-02, Vol.23 (2), p.100818-100818, Article 100818
• Main Authors: Jia, Lemin, Zheng, Wei, Lin, Richeng, Huang, Feng
• Format: Article
• Language: English
• Subjects: Devices; Electronic Materials; Energy Materials
• ISSN: 2589-0042; 2589-0042
• DOI: 10.1016/j.isci.2020.100818

Owing to the fast response speed and low energy consumption, photovoltaic vacuum-ultraviolet (VUV) photodetectors show prominent advantages in the field of space science, high-energy physics, and electronics industry. For photovoltaic devices, it is imperative to boost their open-circuit voltage, which is the most direct indicator to measure the photoelectric conversion capability. In this report, a quasi-Fermi level splitting enhanced effect under illumination, benefiting from the variable Fermi level of graphene, is proposed to significantly increase the potential difference up to 2.45 V between the two ends of p-Gr/i-AlN/n-SiC heterojunction photovoltaic device. In addition, the highest external quantum efficiency of 56.1% (under the VUV irradiation of 172 nm) at 0 V bias and the ultra-fast photoresponse of 45 ns further demonstrate the superiority of high-open-circuit-voltage devices. The proposed device design strategy and the adopted effect provide a referential way for the construction of various photovoltaic devices. [Display omitted] •An open-circuit voltage up to 2.45 V is achieved by the graphene heterojunction device•An efficient band assembly is designed to induce the larger quasi-Fermi level splitting•An EQE as high as 56.1% (172 nm) and a rise time as short as 45 ns are achieved•The adopted effect provides a referential way for various photovoltaic devices Electronic Materials; Energy Materials; Devices