Self-powered topological insulator Bi2Te3/Ge heterojunction photodetector driven by long-lived excitons transfer. (18th June 2022)

• Record Type: Journal Article
• Authors: Yin, Qin; Si, Guoxiang; Li, Jiao; Wali, Sartaj; Ren, Junfeng; Guo, Jiatian; Zhang, Hongbin
• Is Part Of: Nanotechnology. Volume 33:Number 25(2022)
• Publication Date: 2022-06-18
• Subjects: topological insulator -- heterostructure -- exciton transfer -- photodetector -- near-infrared -- ultrafast response; Nanotechnology -- Periodicals; Nanotechnology -- Periodicals; Nanotechnology; Publications périodiques; Nanotechnologies; Periodicals; 620.5
• DOI: 10.1088/1361-6528/ac5df7
• Languages: English
• ISSNs: 0957-4484

Abstract

Abstract: Due to the wide spectral absorption and ultrafast electron dynamical response under optical excitation, topological insulator (TI) was proposed to have appealing application in next-generation photonic and optoelectronic devices. Whereas, the bandgap-free speciality of Dirac surface states usually leads to a quick relaxation of photoexcited carriers, making the transient excitons difficult to manipulate in isolated TIs. Growth of TI Bi2 Te3 /Ge heterostructures can promote the specific lifetime and quantity of long-lived excitons, offering the possibility of designing original near-infrared optoelectronic devices, however, the construction of TI Bi2 Te3 /Ge heterostructures has yet to be investigated. Herein, the high-quality Bi2 Te3 /Ge heterojunction with clear interface was prepared by physical vapor deposition strategy. A significant photoluminescence quenching behaviour was observed by experiments, which was attributed to the spontaneous excitation transfer of electrons at heterointerface via theoretical analysis. Then, a self-powered heterostructure photodetector was fabricated, which demonstrated a maximal detectivity of 1.3 × 10 11 Jones, an optical responsivity of 0.97 A W −1, and ultrafast photoresponse speed (12.1 μ s) under 1064 nm light illumination. This study offers a fundamental understanding of the spontaneous interfacial exciton transfer of TI-based heterostructures, and the as-fabricated photodetectors with excellent performance provided an important step to meet the increasing demand for novel optoelectronic applications in the future.