Near room-temperature chemical vapor deposition of 2D SbI3 on van der Waals substrates for photodetector applications†
Abstract
Two-dimensional (2D) antimony triiodide (SbI3), a layered metal halide with high intrinsic carrier mobility and anisotropic optical properties, holds significant promise for optoelectronic applications. However, the vapor-phase growth of 2D SbI3 thin crystals has remained a significant challenge due to its low melting point (170 °C), which prevents the use of the high substrate temperatures typically needed for efficient nucleation and growth. Here, we report the chemical vapor deposition (CVD) growth of 2D SbI3 crystals at near-room temperature (65 °C) using atomically flat van der Waals (vdW) substrates. Comprehensive characterization via Raman spectroscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) confirms the structural and chemical composition of the synthesized SbI3. Additionally, by employing a two-step CVD strategy, we successfully fabricate SbI3/WS2 vdW heterostructures. Photoluminescence investigations reveal a pronounced interfacial charge transfer between SbI3 and WS2. Leveraging this efficient charge dynamics, we utilize SbI3 thin crystals as photosensitizers to significantly enhance the photoresponse of WS2-based photodetectors. Compared to pristine WS2 devices, the SbI3-modified WS2 photodetector exhibits a notable enhancement in photocurrent by two orders of magnitude, achieving a responsivity of 15.8 mA W−1. This work not only addresses the long-standing challenge of CVD growth of 2D SbI3 but also establishes a platform for exploring interfacial physics and advancing high-performance optoelectronic devices through tailored vdW heterostructures.