非晶SiO_2薄膜中氧双键缺陷电子及光学特性的第一性原理研究

First principles study of the electronic and optical properties of silanone groups in amorphous SiO_2 thin films

利用第一性原理对离子溅射沉积的非晶SiO2薄膜微观结构进行了分析、研究,结果表明,氧双键缺陷(SGs)可以作为体缺陷稳定存在于非晶SiO2中,SGs缺陷导致非晶SiO2薄膜材料禁带中引入了新的电子态,减小了禁带宽度;同时采用时相关密度泛函理论(TDDFT)对其光学特性进行了研究,得到非晶SiO2薄膜介电常数与入射光子能量间的关系曲线,从介电常数的虚部发现SGs缺陷在3.6eV处存在一个光学吸收峰.

This paper reports the studies of the electronic and optical properties of silanone groups （SGs） in a- morphous SiO2 deposited by ion beam sputtering by the first principle method. The results show that, SGs can exists in amorphous SiO2 as bulk defects, SGs defects introduced new electronic states in the band gap of amor- phous SiO2, they reduce the band gap; we use the time dependent density functional theory （TDDFT） to study their optical properties, and get the curve of relationship between the dielectric constant and the incident photon energy, there is an absorption peak at 3.6 eV from the imaginary part of the dielectric constant of SGs defects.