Gate-Tunable Ambipolar Rubrene/WSe2 Polarization-Sensitive Photodetectors

Abstract

Abstract Organic−inorganic heterojunctions have emerged as a promising platform for high-performance photodetectors, yet most existing works integrate organic crystalline or amorphous thin films with 2D inorganic semiconductors, which are fundamentally limited by high defect densities, short exciton diffusion lengths, and the absence of intrinsic optical anisotropy. In this work, we demonstrate high-performance photodetectors by integrating organic single-crystal rubrene with inorganic 2D tungsten diselenide (WSe2). The resulting type-II band alignment can facilitate the efficient separation and transport of photogenerated carriers, while the organic layer significantly enhances the light-harvesting capability of the 2D material. Furthermore, the ambipolar transport characteristics of WSe2 enable excellent gate-tunability of the device. The fabricated device exhibits a low dark current of 218 fA with a responsivity (R) of 3.47 A/W, an external quantum efficiency (EQE) of 838%, and a specific detectivity (D*) of 4.86 × 1010 Jones. Especially, the device shows a polarization-sensitive photoresponse due to the anisotropic optical absorption of the rubrene, rubrene/WSe2 exhibits a dichroic ratio of 1.62 at a wavelength of 514 nm, highlighting their potential for polarization-sensitive detection.