A candidate material EuSn2As2-based terahertz direct detection and imaging

Abstract

Exploring the photoelectric performance of emerging materials represented by graphene, black phosphorus and transition metal dichalcogenides is attracting enormous research interest for a wide range of electronic and photonic applications. The realization of low-power consuming photodetectors with high sensitivity and fast photoresponse in the terahertz band remains one of the profound challenges in optoelectronics. In this study, a material-EuSn₂As₂ has been successfully implemented to realize highly sensitive terahertz photodetectors. The non-equilibrium dynamics in a two-dimensional plane allow an optionally switching between different styles of direct photon-conversions: the analogous photoconductive and photovoltaic modes spontaneously supported by the intrinsic electronic system. The prototype devices exhibited excellent sensitivity of 0.2–1.6 A/W (0.3–2.4 kV/W) from 0.02 to 0.30 THz at room temperature, corresponding to a noise-equivalent power <30pW/Hz^0.5 and a fast response time <16 μs. The versatile switching behaviour and performance of the EuSn₂As₂ flakes-based terahertz detectors were validated via rigorous full-dimension and imaging experiments. These results open the feasibility avenues for low-energy photoelectronic applications of EuSn₂As₂ material.