Theoretical Study On The Electronic Transport And Photocurrent Of The Nickle Atom Junction And Black Phosphorus

Novel electronic nanodevices are the focus of the study today.Low dimensional materials such as one-dimensional metal atom junctions and two-dimensionalblackphosphorushavedemonstratedoutstanding electrical,mechanical and optical properties,showing great potential in applications.In this thesis,we studied the conductance of the nickel metal atom junction which adsorbs hydrogen atoms or molecule.We found that the Ni-H₂-Ni configuration has a conductance of approximately 0.7 G₀,which comes from the strong coherence of the hydrogen molecule's antibonding state between the 3d orbital of the nearby nickel atoms.The conductance of the nickel junction with a single H atom is close to 1G₀,with a weak spin polarization.The spin-down channel plays a leading role in the larger interconnection gap.Next,we studied the photogalvanic effect of the phosphorene-based photodector.We found that the space inversion symmetry of the phosphorene can be broken by the gate voltage or by a heterostructure with the blue phosphorous.A robust photocurrent can be generated under the illumination of the polarized light for the gated phosphorene and black phosphorous/blue phosphorus heterostructure,without applying any source-drain bias.The photocurrent of the hesterostructure can be several orders in magnitude larger than that of the gated phosphorene.The extinction ratio is about several hundreds.Finally,the electrical transport properties of the one-dimensional Ni-O metal junction are investigated under low bias or at low temperature difference.We obtained that within the bias range of 0¹00 m V,the tunnel junction has the stable tunneling magnetoresistance and spin injection rate greater than 60%.The spin injection rate of the antiparallel case is above 45%with the low temperature difference range of 20²00K,and the spin up and down electrons has an opposite transport direction.