Theoretical Study On Schottky Regulation Of Graphene Heterostructure Doped With Nonmetallic Elements

The main work of this paper is to explore the regulation of graphene heterojunction types and Schottky barrier height by non-metal elements doping.The effects of nonmetallic elements on the structure and properties of graphene/graphene and tungsten WSe2/graphene heterojunction are discussed through the first principles.These will provide guidance for design and manufacture of the 2d FET.The effect of doping of nonmetallic elements on the electron structure of graphene/graphene heterojunction was studied by density functional theory.The results show that when B atom doped AB stacks graphener/graphene heterojunction at the T and H sites,the heterojunction exhibits p-type semiconductor properties,and the band gap values at the T and H sites are 0.22 and 0.30 eV respectively.When N atom doped AB stacks graphene/graphene heterojunction at the T and H sites,the heterejunction exhibits n-type semiconductor properties,and the band gap values at the T and H sites are 0.20 and 0.31 eV,respectively.When the a-atom doped AB stacks the graphene/graphene heterojunction at the H position,the impurity level appears near the Fermi level,and the heterojunction is p-type.When T-doped,the heterojunction appears n-type.The results show that the H position can effectively destroy the spatial structure symmetry of the double-layer graphene and open the band gap.When B and N atoms are doped with AB to stack graphene/graphene heterojunction at the t-position and the h-position,the band gap is different due to the doping atom distance.The results show that the doped atom distance can be an effective method to control the electron characteristics.The effect of doping of nonmetallic elements on the electronic properties of tungsten WSe2/graphene schottky was studied by using the plane-wave supersoft pseudopotential method.It is shown that the stable structure is formed by the combination of van der Waals force between the layers of tungsten WSe2 and graphene.The band result indicated that the p-type swhottky barrier was formed between tungsten WSe2 and graphene at the stable layer spacing.The three-dimensional difference diagram of electron density shows that the electrons in graphene move towards tungsten WSe2,making the surface of tungsten WSe2 negatively charged and the surface of graphene positively charged,and forming an internal electric field at the interface.The analysis shows that doping tungsten WSe2 with nonmetallic atoms can effectively regulate the type and height of tungsten WSe2/graphene schottky barrier.When C and O atoms are doped with tungsten WSe2,schottky type is converted from p type to n type,and the height of schottky barrier is effectively reduced.When N and B atoms are doped with tungsten WSe2,the doped tungsten WSe2 system exhibits gold properties,and the contact with graphene is ohmic.