Optoelectronic Properties Of N Doped SnO₂

SnO₂with advantage of wide band gap and exciton binding as Oxide semiconductoris considered to be the ideal candidate for the next generation of semiconductor materialsof optoelectronic materials. The doping oxide semiconductor has excellent optical,magnetic and electrical properties. But SnO₂-based doped oxide semiconductor had notbeen a real application; this is because of the unclear mechanism of SnO₂doped andelectrical properties. This paper is based on density functional theory （DFT） FirstPrinciples. Superlattice structure of doped SnO₂was analysis through the full-potentiallinearized augmented plane wave method （FPLAPW） and the generalized gradientapproximation （GGA）. All works were carried out in the WIEN2K software.First, the electronic structure of Sn1-χNχO2materials was simulation analyzed. Theresults showed that the system of band gap was narrowed. This was due to the2p stateelectron of Nitrogen into outer orbit of O, Sn and hybrid. A narrow deeply main level wasformed in the energy range of1.63².38eV, that is the impurity level. The analysis resultshowed that the N element is the ideal p-type dopant. Doped material had semi-metallicproperties and enhanced the conductive properties. Dielectric function and opticalabsorption spectra produced three main transition peaks with red-shift, Optical absorptionedge and the optical response of the material was increased. It was due to mainly electronictransition absorption.In order to deeply understand the performance of SnO₂doping Nitrogen, theelectronic structure of SnO₂crystal with dopping different Nitrogen concentrations and thedensity of system states, band structure and optical dielectric function were studied. Theresults showed that the band gap of the doped system was decreased and then increased.Band gap was narrowest at12.5%N, and conductive performance was strongest. Fermilevel was moved to the lower energy side and into the valence band. A narrow, shallowacceptor level was made in the range of0.55¹.05eV. The carrier-holes increased nearly bythe top of the valence band. The energy level prodced splitting and orbit overlaps in thevalence band and conduction band. The number of electronic layout, magnetic moment and total energy of unit cell as the doping concentration is larger was increased with the moredoping concentration. N atoms determine the size of the magnetic moment. The three maintransition peaks were appeared in the spectrum of the imaginary part of the function.Transition peak is arising from the electronic transitions between energy levels. Opticalabsorption edge was broadened. The main transition peak occurred at a redshift.Reflectivity associated with dielectric spectroscopy, the transition peak related to theabsorption of electron transition.We research on the electronic structure of SnO₂supercell structure doped different Nconcentration. The results showed that Fermi level was moved to the lower energy side.Band gap gradually decreased as the doping amount of the increase. Compared witheigenstates of the electronic structure, the impurity band was formed in the energy range of1.35to2.50eV, and the dielectric imaginary part of the function spectrum was littlechanged. Four transition peaks were appeared in the energy of2.5eV,6.750eV,8.75eV and10.0eV. The three main transition peak lines moved to lower energy side and occurredredshift. Transition peak related to electronic transition absorption corresponds to the figureof refractive index. Refractive index gradually decreased along with the doping amount ofthe increase.Then, Intrinsic and N: SnO₂materials anti-site substitution, electronic density of statesand optical properties （dielectric function, reflectivity, refractive index, absorptioncoefficient） were studied. The results showed that the antisite alternative system had themetal features. The spin polarization of N-doped system exhibiting semi-metallicproperties was closed to100%.The material. The band gap of the doped system wasrelatively wider. The conductive properties of the anti-alternative material was Enhancedrelatived to pure SnO₂materials. The optical properties of the material changed. Newdielectric peak was made by N-2p orbital electron transition to Sn-5S orbital. Reflectivity,refractive index, the absorption coefficient occured the blue shift. These results provided atheoretical basis for the anti-site substitution at the electrical and optical.In the end, electronic density of states, dielectric function, refractive index andreflectivity of N-doped SnO₂thin film materials was calculated.it showed that the twostructures undoped were semiconductor materials. In top of the price band, there were more electronic. After doping, In the Fermi level electron distributed in the spin-down density ofstates, but no in the spin-up.Spin polarization rate of system with semi-metalliccharacteristics and stronger conductive properties reached100%. This was mainly derivedfrom N-2p orbital electronic. Energy loss function, reflectivity, refractive index correspondto dielectric function. Each transition peak associated transition between the electronic.Three main transition peaks was produced. There was a new transition peak produced dueto the introduction of N atoms after doping. The optical and electrical properties of thesystem obviously changed after doping Nitrogen.