Graphene/SrTiO3 interface-based UV photodetectors with high responsivity

• 来源期刊: 中国物理B（英文版）
• 年，卷（期）: 2021,（3）
• 所属期刊栏目: INTERDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY
• 页码范围: 611-617
• 页数: 7页
• 语种: 英文
• DOI: 10.1088/1674-1056/abda2e

摘要

Strontium titanate(SrTiO3),which is a crucial perovskite oxide with a direct energy band gap of 3.2 eV,holds great promise for ultraviolet(UV)photodetection.However,the response performance of the conventional SrTiO3-based pho-todetectors is limited by the large relative dielectric constant of the material,which reduces the internal electric field for electron-hole pair separation to form a current collected by electrodes.Recently,graphene/semiconductor hybrid photode-tectors by van-der-Waals heteroepitaxy method demonstrate ultrahigh sensitivity,which is benefit from the interface junc-tion architecture and then prolonged lifetime of photoexcited carriers.Here,a graphene/SrTi03 interface-based photode-tector is demonstrated with an ultrahigh responsivity of 1.2 x 106 A/W at the wavelength of 325 nm and～2.4 x 104 A/W at 261 nm.The corresponding response time is in the order of～ms.Compared with graphene/GaN interface junction-based hybrid photodetectors,～2 orders of magnitude improvement of the ultrahigh responsivity originates from a gain mechanism which correlates with the large work function difference induced long photo-carrier lifetime as well as the low background carrier density.The performance of high responsivity and fast response speed facilitates SrTiO3 material for further efforts seeking practical applications.