Hybrid 1D/2D heterostructure with electronic structure engineering toward high-sensitivity and polarization-dependent photodetector

Abstract

The widespread application of photodetectors has triggered an urgent need for high-sensitivity and polarization-dependent photodetection. In this field, the two-dimensional (2D) tungsten disulfide (WS2) exhibits intriguing optical and electronic properties, making it an attractive photosensitive material for optoelectronic applications. However, the lack of an effective built-in electric field and photoconductive gain mechanism in 2D WS2 impedes its application in high-performance photodetectors. Herein, we propose a hybrid heterostructure photodetector that contains 1D Te and 2D WS2. In this device, 1D Te induces in-plane strain in 2D WS2, which regulates the electronic structures of local WS2 and gives rise to type-II band alignment in the horizontal direction. Moreover, the vertical heterojunction built of 2D WS2 and 1D Te introduces a high photoconductive gain. Benefiting from these two effects, the transfer of photogenerated carriers is optimized, and the proposed photodetector exhibits high sensitivity (photoresponsivity of ~27.7 A W−1, detectivity of 9.5 × 1012 Jones, and short rise/decay time of 19.3/17.6 ms). In addition, anisotropic photodetection characteristics with a dichroic ratio up to 2.1 are achieved. This hybrid 1D/2D heterostructure overcomes the inherent limitations of each material and realizes novel properties, opening up a new avenue towards constructing multifunctional optoelectronic devices.