Epitaxial Topological Insulator Bi2Te3 for Fast Visible to Mid-Infrared Heterojunction Photodetector by Graphene As Charge Collection Medium

Xingchao Zhang; Xianchao Liu; Chaoyi Zhang; Silu Peng; Hongxi Zhou; Liang He; Jun Gou; Xinran Wang; Jun Wang

doi:10.1021/acsnano.2c00435

Epitaxial Topological Insulator Bi₂Te₃ for Fast Visible to Mid-Infrared Heterojunction Photodetector by Graphene As Charge Collection Medium

ACS Nano. 2022 Mar 22;16(3):4851-4860. doi: 10.1021/acsnano.2c00435. Epub 2022 Mar 11.

Authors

Xingchao Zhang¹, Xianchao Liu¹, Chaoyi Zhang¹, Silu Peng¹, Hongxi Zhou¹, Liang He², Jun Gou¹, Xinran Wang², Jun Wang^{1

3}

Affiliations

¹ School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China.
² National Laboratory of Solid-state Microstructures, School of Electronic Science and Engineering, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China.
³ State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China.

PMID: 35274530
DOI: 10.1021/acsnano.2c00435

Abstract

Three dimensional topological insulators have a thriving application prospect in broadband photodetectors due to the possessed topological quantum states. Herein, a large area and uniform topological insulator bismuth telluride (Bi₂Te₃) layer with high crystalline quality is directly epitaxial grown on GaAs(111)B wafer using a molecular beam epitaxy process, ensuring efficient out-of-plane carriers transportation due to reduced interface defects influence. By tiling monolayer graphene (Gr) on the as-prepared Bi₂Te₃ layer, a Gr/Bi₂Te₃/GaAs heterojunction array prototype was further fabricated, and our photodetector array exhibited the capability of sensing ultrabroad photodetection wavebands from visible (405 nm) to mid-infrared (4.5 μm) with a high specific detectivity (D*) up to 10¹² Jones and a fast response speed at about microseconds at room temperature. The enhanced device performance can be attributed to enhanced light-matter interaction at the high-quality heterointerface of Bi₂Te₃/GaAs and improved carrier collection efficiency through graphene as a charge collection medium, indicating an application prospect of topological insulator Bi₂Te₃ for fast-speed broadband photodetection up to a mid-infrared waveband. This work demonstrated the potential of integrated topological quantum materials with a conventional functional substrate to fabricate the next generation of broadband photodetection devices for uncooled focal plane array or infrared communication systems in future.

Keywords: Bi2Te3; broadband photodetection; fast photodetector; mid-infrared; topological insulator.