Wet Chemistry Vitrification and Metal-to-Semiconductor Transition of 2D Gray Arsenene Nanoflakes

To manipulate the electrical and optical properties of 2D materials via engineering their phases and crystallinity is of great significance for the construction of nanodevices with versatile functions. Herein, the controllable transformation of semimetallic gray arsenene nanoflakes into semiconducting vitreous arsenene nanoflakes via a wet chemistry vitrification method is reported. Experimental studies and theoretical simulations reveal that the vitrification of gray arsenene nanoflakes is attributed to the consumption of arsenic atoms by aqueous HF via the trigger of dissolved oxygen, resulting in a significant variation of band structure rendered by the formation of atomic structure disorderliness and arsenic atom defects/vacancies. Unlike the semimetallic features of pristine gray arsenene nanoflakes, the as-prepared vitreous arsenene nanoflakes exhibit a strong photoluminescence peak centered at 635 nm corresponding to an optical band gap of 1.95 eV, and the field-effect transistors based on vitreous arsenene nanoflakes also exhibit definitely p-type semiconducting characteristics with a carrier mobility of approximate to 159.1 cm(2) V-1 s(-1). The wet chemistry induced vitrification of gray arsenene nanoflakes presents an efficient strategy to regulate the electrical and optical properties of arsenene nanoflakes, providing new insights for the interface and band structure engineering of 2D nanomaterials.