Electronic Structure Regulation Mechanism Of Indium Selenide Nanostructures

Recently,graphene has promoted an upsurge in the research of two-dimensional materials.Currently,there are many two-dimensional materials that have attracted extensive attention of researchers,and including InSe.Similar to other two-dimensional materials,InSe material has relatively strong interlayer atomic interaction,and the interlayer is combined by weak van der Waals force,with the interlayer spacing is about 0.8nm,and the atomic plane is arranged of Se-In-In-Se.It has a high carrier mobility about 10³cm² v^-1 s^-1.In terms of catalytic activity of electrocatalytic hydrogen evolution reaction,InSe shows high activity and stability,and its catalytic activity can be regulated by modification of band and edge characteristics,so it has a good prospect.In this paper,the characteristics of its electronic structure are optimized mainly through the atomic-level modification of its structure.The following detailed exploration is carried out from the aspects of hydrogen evolution performance of materials,magnetic doping and electronic characteristics of Janus structure.(1)Firstly,the hydrogen evolution performance of one-dimensional InSe nanoribbon was explored by using the First-principle calculation.Through the comparative study of adsorption characteristics at different In and Se points and corresponding vacancies In the Zigzag InSe nanoribbon,it was concluded that the edge state could promote the activity of electrocatalytic hydrogen evolution.In addition,the hydrogen evolution activity can be further enhanced by introducing holes into the plane.This enhancement is closely related to the hybridization between s orbitals of H atoms and p orbitals of In and Se atoms.These interatomic interactions result in obvious local gap states at the Fermi energy level,which are characterized by enhanced hydrogen evolution.Meanwhile,this interaction leads to electron transfer and enrichment at the hydrogen adsorption sites,which weakens the hydrogen adsorption and reduces the desorption energy during hydrogen evolution.(2)The modification of monolayer InSe magnetic properties by transition metal doping in the fourth period was studied,and it was found that Mn doping exhibited magnetic ground state characteristics with stable energy,and the hybridization of s,p-d orbitals between Mn doping and body adjacent In or Se atoms led to the band gap state of energy level splitting near Fermi level.To explore the magnetic exchange mechanism,two Mn-doped atoms were introduced.The results show that the two Mn atoms form an energy stable ferromagnetic interaction in the form of Mn-In-Se-Mn hybrid chain,which has high anisotropy and direction dependence.Our results reveal that the Mn-InSe system has a good application prospect in spintronics devices.(3)The evolution process of the electronic properties of InSe-like single-layer sulfur compound Janus structure was analyzed,and the direct band gap inside the In₂Se Te-Janus structure was found,and the interaction between the layers was enhanced by the strong coupling of p_z orbitals between Se atoms and sublayer Te atoms,and the band gap was significantly changed.In addition,the effective mass analysis of the holes in In₂Se Te established that the structure was an ideal choice for p-type semiconductors.By comparing the internal and external electric fields to break the mirror symmetry of Janus structure,and by providing additional channels to adjust its electronic structure in the valence band.The structural of In₂Se Te-Janus structure provides a new approach for the application of two-dimensional materials in optoelectronic nano-devices.