Computational Design Of Two-dimensional Emerging Electronic Devices Based On First Principles

Nowadays,with the rapid development of science and technology,emerging materials of the nanoscale are spring up,and various quantum effects have become important elements to affect the performance of materials and devices.In this case,material design methods based on first principles,especially ab initio methods based on density functional theory?DFT?,have begun to play a more important role in emerging material design.Using the density functional theory combined with the non-equilibrium Green's function method,we studied the quantum transport properties of MoS₂ junctionless transistor and the influence of bending deformation on transport properties of flexible all black phosphorus devices,and calculated the transport properties with different doping along different direction.Firstly,based on the density functional theory method in combination with the nonequilibrium green's function formalism,the band structures of MoS₂ NR passivated by H and doped by VCA were investigated in this work.A large subbandgap appeared over the fermi level in the band structure when MoS₂ NR passivated by H,and the VCA doping with the doping concentration 1.81×1013/cm2 made the MoS₂ NR appear metallic.Using first principles quantum transport calculations based on a four probe model,we calculated the quantum transport properties of a MoS₂ junctionless transistor with considering the atomic details of the gate material and the effects of the gate to the transistor.The results showed that atomic level polysilanes molecule gate can better turn off the N-type MoS₂ junctionless transistor than the P-type one.Secondly,using the density functional theory combined with the nonequilibrium Green's function method,we studied the influence of bending deformation on transport properties of flexible all black phosphorus devices,and calculated the transport properties with different doping along different direction.The results showed that bending angles had obvious influence on the transport properties of the P-type device along armchair direction and the N-type along zigzag direction.