First Principles Study Of Electronic And Structural-Properties Of Low Dimensional Nanomaterials

Low-dimensional nanomaterials have attracted extensive attention in industry and academia due to their rich physicochemical properties.The existing two-dimensional materials are used in large application areas,especially in transistors,optoelectronics,energy storage systems and in other applications.The 2D like graphene limits their application in optoelectronics due to the absence of a band gap.Similarly,the 2D silicene limits its application due to environmental stability.By considering these aspects of limitations of existing 2D materials,the search of new two and one-dimensional materials are at its peak.Based on Mo2C,InP3,and InSb materials,we examine the electronic,magnetic and electrocatalytic properties of one-dimensional nanotubes and two-dimensional nanosheet to explore their applications in spintronic,optoelectronics and catalytic reactions.In this thesis,we present the structural,electronic,and magnetic properties of single-walled Mo2C nanotubes investigated by using first-principles calculations.We establish that single-walled Mo2C nanotubes can be rolling up from graphene-like Mo2C monolayer with H-or T-type phase,i.e.,H-Mo2C and T-Mo2C nanotubes.Further,we have explained the comparisons of energies and magnetic properties of both types of nanotubes and monolayers.In search of new two-dimensional materials,we purpose a new phosphorene like InP3 structure by cleaving(0-11)surface of bulk InP3 The predicted black phosphorene like(BP-InP3)structure shows excellent performance for Hydrogen evolution reaction comparable to Pt.Secondly,we have compared the electronic and structural properties of graphene like(G-InP3)and BP-InP3 structure and observe BP-InP3 phosphorene like InP3 is energetically more stable than the reported configuration.Motivated by recent experimental studies on Free standing two-dimensional single crystalline InSb Nanosheet,we have explored the electronic properties of two-dimensional InSb and nanotubes.InSb monolayer has high electron and hole mobility?7×103 and 0.7×102 respectively.On rolling the monolayer to nanotubes in an armchair and zigzag direction,optimized parameters,energy levels and electronic structure of corresponding nanotubes are compared.Finally,we have performed the computational study to support the experimental work of refining defect states in W18049 by Mo doping.