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• Photonics Research
• Vol. 10, Issue 10, 2302 (2022)
Shi Zhang1、2、3、†, Chaofan Shi1、3、†, Weiwei Tang1, Libo Zhang1、2、4, Li Han1、2、4, Chengsen Yang1、3, Zhengyang Zhang1、3, Jian Wang2, Miao Cai5, Guanhai Li1、2、6、*, Changlong Liu1、2、7、*, Lin Wang2, Xiaoshuang Chen1、2、8、*, and Wei Lu1、2
Author Affiliations
• 1College of Physics and Optoelectronic Engineering, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
• 2State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physicshttps://ror.org/02txedb84, Chinese Academy of Sciences, Shanghai 200083, China
• 3Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
• 4Department of Optoelectronic Science and Engineering, Donghua University, Shanghai 201620, China
• 5Terahertz Technology Innovation Research Institute, Shanghai Key Laboratory of Modern Optical System, University of Shanghai for Science and Technology, Shanghai 200093, China
• 6e-mail: ghli0120@mail.sitp.ac.cn
• 7e-mail: clliu@ucas.ac.cn
• 8e-mail: xschen@mail.sitp.ac.cn
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Shi Zhang, Chaofan Shi, Weiwei Tang, Libo Zhang, Li Han, Chengsen Yang, Zhengyang Zhang, Jian Wang, Miao Cai, Guanhai Li, Changlong Liu, Lin Wang, Xiaoshuang Chen, Wei Lu. High-frequency enhanced response based on Sb2Te3 topological insulators[J]. Photonics Research, 2022, 10(10): 2302 Copy Citation Text show less

Abstract

Topological insulators represent a new quantum phase of matter with spin-polarized surface states that are protected from backscattering, exhibiting electronic responses to light, such as topological quantum phase transitions. However, the effects of high-frequency driving topological intrinsic systems have remained largely unexplored challenges experimentally for high-sensitivity terahertz detection. In this study, by integrating $Sb2Te3$ topological insulators with subwavelength metal antennas through micro-nano processing, a high-frequency terahertz detector with high sensitivity is proposed. The enhanced response originates from the asymmetric scattering of the surface electrons in the $Sb2Te3$ flakes induced by the terahertz wave. The device displays room-temperature photodetection with a responsivity of 192 mA/W and equivalent noise power of less than $0.35 nW/Hz1/2$ in the frequency range from 0.02 to 0.3 THz. These results pave the way for the exploitation of topological insulators for high-frequency operation in real-time imaging within long-wavelength optoelectronics.

1. INTRODUCTION

The terahertz (THz) region of the electromagnetic spectrum ranging from 0.1 to 10 THz [1] is a spectral window with rich scientific opportunities and exhibits great promise in applications [24]. For example, in the field of investigating matter, THz spectroscopy serves as a unique tool because many molecules have structural absorption resonance at these frequencies [5]. THz waves can penetrate numerous commonly used dielectric materials, which are opaque for visible and mid-infrared light, making them a unique tool for defense and security systems [6]. In the field of electronics, the THz range constitutes the ultimate limit of operation for high-frequency electronics. However, this region has been considered the scientific gap in the electromagnetic spectrum [7]. One of the issues is the lack of sensitive THz detectors. Many optoelectronic detection technologies that are widely used in the visible and infrared regimes cannot be easily translated to this long-wavelength regime because THz photon energies are far below typical electronic interband transitions [8]. The need for a cryogenic system due to the few meV photon energy of the THz wave sets up obstacles for the miniaturization of THz detectors.

Shi Zhang, Chaofan Shi, Weiwei Tang, Libo Zhang, Li Han, Chengsen Yang, Zhengyang Zhang, Jian Wang, Miao Cai, Guanhai Li, Changlong Liu, Lin Wang, Xiaoshuang Chen, Wei Lu. High-frequency enhanced response based on Sb2Te3 topological insulators[J]. Photonics Research, 2022, 10(10): 2302