Selective growth of wide band gap atomically thin Sb₂O₃ inorganic molecular crystal on WS₂

Heterostructures combined by different individual two-dimensional (2D) materials are essential building blocks to realize unique electronic, optoelectronic properties and multifunctional applications. To date, the direct growth of 2D/2D atomic van der Waals heterostructures (vdWHs) have been extensively investigated. However, the heterostructures from 2D inorganic molecular crystals and atomic crystals have been rarely reported. Here we report two-step direct epitaxial growth of the inorganic molecular-atomic Sb₂O₃/WS₂ vdWHs. The thickness of Sb₂O₃ nanosheets on WS₂ nanosheets can be tuned by variable growth temperatures. Oriented growth behavior of Sb₂O₃ on WS₂ was determined through statistics. Optical images, Raman spectra, Raman mappings and selected-area electron diffraction (SAED), etc., reveal that Sb₂O₃/WS₂ heterostructures are vertically stacked with high crystal quality. Electrical transport measurements demonstrate that the heterotransistors based on the heterostructures possess high current on/off ratio of 5 × 10⁵, obvious gate-tunable and current rectification output characteristics. Optoelectronic characterizations show that the heterostructures have a clear photoresponse with high responsivity of 16.4 A/W. The growth of vdWHs from 2D inorganic molecular-atomic crystals may open up new opportunities in 2D functional electronics and optoelectronics.