Te掺杂对二维InSe抗氧化性以及电子结构的影响

Effect of Te doping on oxidation resistance and electronic structure of two-dimensional InSe

In Se作为一种典型的二维层状半导体材料,具有优异的电学性能以及适中可调的带隙,在光电器件中表现出诱人的应用前景.然而有研究表明,单硒空位(Vse)体系的In Se易受O_(2)分子影响,造成In Se材料降解,严重影响其在电子器件领域的应用.本文基于In Se降解机理,提出了碲(Te)替位掺杂的方法,用于提升该材料的环境稳定性.利用密度泛函理论对不同体系电子结构、吸附能、能量反应路径等进行分析,发现Te掺杂不仅显著改善缺陷引起的In Se降解问题,同时可消除Vse产生的缺陷态,起到缺陷补偿作用.具体研究结果如下:1)O_(2)分子在Te掺杂In Se表面(In Se-Te)的解离能垒高达2.67 e V,说明其具有较强的抗氧化能力;2)O_(2)分子在In Se-Te表面保持3.87A的距离,吸附能仅有-0.03 e V,表明O_(2)分子物理吸附在其单层表面;3)Te掺杂不仅提升材料抗氧化能力,同时还消除了Vse产生的缺陷态.该研究结果将有助于进一步提升In Se二维材料器件的环境稳定性,推动In Se二维器件研究和发展.

InSe is a typical two-dimensional(2D)layered semiconductor material,which has excellent electrical properties and moderate adjustable band gap.It is found that InSe has an attractive application prospect in optoelectronic devices.However,some studies have shown that InSe in a single selenium vacancy(Vse)system is easily degraded when exposed to the environment of O_(2)molecule,which seriously affects the application of InSe in the field of electronic devices.In order to improve the environmental stability of the material,the substitution doping method of Te is proposed in this work.Density functional theory(DFT)is used to analyze the electronic structure,adsorption energy,Bader charge and energy reaction paths of the different systems.It is found that Te substitution doping can significantly improve the stability of InSe.At the same time,the defect state produced by Vse can be eliminated.The specific research results are as follows.First,the dissociation barrier of O_(2)molecule on Te doped InSe surface(InSe-Te)is as high as 2.67 eV,indicating that Te-doped InSe has a strong antioxidant capacity.Second,the distance between O_(2)molecule and the surface of InSe-Te is 3.87Å,and the adsorption energy is only-0.03 eV,indicating that O_(2)molecules are physically adsorbed on the monolayer surface.Third,Te doping not only improves the antioxidant capacity of the InSe,but also eliminates the defect state produced by Vse.Fourth,the Te-doping obviously eliminates the original Vse defect state or impurity band.The density of states and band structure of Te-doped InSe are almost the same as those of perfect InSe,which can maintain the stability of InSe structure and effectively reduce the damage of oxidation environment to defective InSe monolayer.The results of this study will be helpful in improving the environmental stability of InSe 2D material devices and promoting the research and development of InSe 2D devices.