The Theoretical Study Of Graphene-like In_xAl_1-xN Materials

In_xAl_1-xN is an important member of the third-generation GaN series and has excellent photoelectric properties.In particular,the two-dimensional In_xAl_1-xN has the excellent performance and nano-size effect of the In_xAl_1-xN alloy,which can improve the absorption of the infrared-visible-ultraviolet light wave of the nitride semiconductor material,and is widely used in the research of optoelectronic devices.In this thesis,five types of single-layer In_xAl_1-xN?x=0,0.25,0.5,0.75,1?models based on density functional theory were constructed using Material Studio 8.0 software,and their photoelectric properties were explored.The experimental results show that the five types of single-layer In_xAl_1-xN materials belong to the indirect band gap;with the increase of x,the lattice constant increases gradually,and the forbidden band width varies from 2.939eV to0.524eV;In the imaginary part curve of the function,as the In component increases,the highest peak shifts from 6.08eV to 4.67eV,resulting in a red shift phenomenon,and the peak value is getting higher and higher,indicating that the electronic transition capability is increased.The photoelectric properties of eight single-layer models of Mg-substituted?In or Al?doped In_xAl_1-xN were studied theoretically.The results show that the binding of Mg to the substitutional doping model of In is more stable under the same composition.Mg doping makes the system become a p-type semiconductor,and the lattice constant is gradually increased;the absorption of ultraviolet light by the material is improved.In addition,the anti-loss ability is also improved,but the anti-loss ability of Mg-In is weaker than that of Mg-Al;for Si-doped single-layer In_xA_l-xN,the Si-In is a single layer of Si-Al under the same composition.The model is more stable.After doping,the energy bands are all moved down.The electrons can only transition to the conduction band with less energy.The density of states shifts to the low energy direction,which improves the conductivity of the material and facilitates the formation of n-type semiconductors.Blue shift occurs and the resistance to wear is enhanced.On the basis of single layer,the adsorption performance of CO and O₂ molecules was studied for the graphene-like In_0.5Al_0.5N with a composition of 0.5,The stable positions of both were directly above the Al atoms,and the adsorption effect of O₂ after adsorption.Preferably,the adsorption energy is-1.06 eV,the O₂ molecule mainly generates charge transfer with surface metal atoms,and the charge transfer amount of the Al atom is large;the interaction between CO molecules and monolayer surfaces is less than that of O₂,and there is a weak physical adsorption.Finally,a two-layer model was constructed on a single layer.It was found that the adsorption position of the double layer on the O₂ molecule was also positive above the Al atom,and the adsorption energy reached-2.17 eV;There is a strong interaction,typical chemisorption;the adsorption of CO can be increased by 0.24 eV.The comparison shows that the graphene-like In_0.5Al_0.5N structure has a good adsorption effect on O₂.