Growth And Characterization Study Of Antimonene Grown By Molecular Beam Epitaxy

As one of the intriging 2D materials,antimonene has many unique properties that are different from its bulk counterpart.These properties include a tunable band gap by biaxial strain,the transition from indirect band gap to direct band gap,and the topological insulating property.Moreover,antimonene has been reported to have high electrical mobility and chemical stability in atmosphere.Many theoretical and experimental efforts have focused on the growth and characterization of antimonene.However,to grow high quality,especially large-area antimonene remains challenging.In this study,we report the direct growth approach of antimonene on c-plane sapphire substrate and Si(111)substrate using molecular beam epitaxy(MBE)and present micro-scale antimonene on nonpolar substrates for the first time.Prior to the growth,substrates need to be treated to make sure a clean and smooth surface.We explore the effect of growth temperature on antimonene formation and surface morphology and use X-ray diffraction to confirm the formation and quality of the antimonene samples.Finally,we summarize and present a growth phase diagram of antimony as a function of growth temperature.In addition,we have found different molecular configurations of the antimony source(Sb2 or Sb4,depending on the cracking temperature)can affect the electrical properties of the grown samples dramatically.Besides,we observed photoluminescence singals at 1.7eV,which supports the presence of antimonene.Finally,it is proved to be stable in the air and has a high electrical mobility,which exceeds 70cm2/V·s.This work didn't involve excess growth procedures such as using a buffer layer or surfactant to enhance the growth.We choose low cost commercialized substrates to growth antimonene directly on which may pave the way for the transition from fundamental studies to mass production.Finally,this work offers a new method of antimonene growth and provides opportunities to enhance van der Waals epitaxy of 2D materials.