Spiral Growth of SnSe2 Crystals by Chemical Vapor Deposition

Although a lot of work has been reported on the growth and properties of 2D atomic layered materials, the growth mechanism for these crystals via the chemical vapor deposition method (CVD) has remained elusive. Here, a screw dislocation–driven spiral growth of SnSe 2 crystal flakes via CVD is reported. The polymorph of as‐synthesized SnSe 2 crystals is verified as 1T‐phase by both experimental characterization and theoretical calculation. The density functional theory study reveals morphology transformation during the growth process while phase‐field modeling unravels the screw dislocation propagation to form the pyramid‐like structure of SnSe 2 . The optical band gap of SnSe 2 crystals relates to an indirect band gap of 1.0 eV. The photodetector devices based on SnSe 2 crystals exhibit high responsivity and ultrafast response time in the microsecond regime.