Controlled Synthesis of High-Quality Monolayered α-In₂Se₃ via Physical Vapor Deposition

In this work, we have demonstrated the synthesis of high-quality monolayered α-In₂Se₃ using physical vapor deposition method under atmospheric pressure. The quality of the In₂Se₃ atomic layers has been confirmed by complementary characterization technologies such as Raman/photoluminescence spectroscopies and atomic force microscope. The atomically resolved images have been obtained by the annular dark-field scanning transmission electron microscope. The field-effect transistors have been fabricated using the atomically layered In₂Se₃ and exhibit p-type semiconducting behaviors with the mobility up to 2.5 cm²/ Vs. The In₂Se₃ layers also show a good photoresponsivity of 340A/W, as well as 6 ms response time for the rise and 12 ms for the fall. These results make In₂Se₃ atomic layers a promising candidate for the optoelectronic and photosensitive device applications.