Ultra-broadband, fast, and polarization-sensitive photoresponse of low-symmetry 2D NdSb2

Broadband photodetectors with polarization-sensitive ability have received extraordinary attention for modern optoelectronic devices. Ideal photodetectors should possess high responsivity, fast response, and good stability, which are rare to meet at the same time in one low-symmetric two-dimentional (2D) material. In this work, neodymium diantimonides (NdSb2), a member of light rare-earth diantimonides RSb2 (R = La-Nd, Sm) with low-symmetry structure, is introduced as a fascinating highly anisotropic 2D material for broadband detection (532 nm to 4 mu m). The photodetector exhibits a responsivity of 0.49 mA.W-1 with 15 mu s response time at 532 nm and highly stable performance under ambient conditions over 8 months. Furthermore, we identify the polarization-sensitive photoresponse of the detector and demonstrate a high anisotropic factor ( )similar to 1.6. In addition, strong in-plane anisotropy is revealed by anisotropic phonon response and the photodetection mechanism is investigated by scanning photocurrent microscopy measurements. This pioneer work on NdSb2 paves the way for further exploration of 2D RSb2 for high performance polarized photodetectors with fast photothermoelectric response.

Automated summary

Broadband photodetectors with polarization-sensitive ability have attracted significant attention for their potential use in optoelectronic devices. In this work, a low-symmetry two-dimensional material, neodymium diantimonides (NdSb2), is introduced as a highly anisotropic material for broadband detection. The photodetector demonstrates high responsivity and fast response time at 532 nm, as well as stable performance over a long period of time. The polarization sensitivity and anisotropic factor of the detector are also investigated, revealing its potential for high-performance polarized photodetectors.