南京大学学报（自然科学版）2017，Vol.53Issue(3)：392-398,7.DOI:10.13232/j.cnki.jnju.2017.03.002
非晶掺氧氮化硅薄膜中N-Si-O发光缺陷态的研究
Investigation on luminescent defect state related to N-Si-O bondingin amorphous oxygenated Silicon nitride film
摘要
Abstract
In order to investigate deeply the luminescent mechanism of amorphous oxygenated Silicon nitride(a-SiNx∶O)film,the a-SiNx∶O thin films were prepared by plasma enhanced chemical vapor deposition(PECVD)at room temperature.By adjusting the flow rate ratio(R)of silane(SiH4)to ammonia(NH3),photoluminescence(PL)with peak position tunable in the visible range from 2.06 to 2.79 eV can be realized.In absorption spectra of a-SiNx∶O films,the location of absorption peaks were in good agreement with those of corresponding PL.It suggested that the PL originates from radiative recombination at luminescent defect state.Based on the calculation of the energy distance between optical absorption edge and the position of absorption peak,the location of this luminescent defect state was determined to be about 0.65 eV underneath the absorption edge.From the analysis on bonding concentration in Fourier transform infrared(FTIR)spectra and the deconvolution of Si 2p peak in X-ray photoelectron spectra(XPS),it was found that the enhancement of PL was proportional to the increase of N-Si-O bonding concentration.Both of the PL intensity and N-Si-O bonding concentration reached the maximum when R=1∶4.The experimental results further certified that luminescent defect state in a-SiNx∶O film was closely related to N-Si-O bonding configuration.Finally,an energy band model for photoluminescence of a-SiNx∶O films was constructed.The carriers were pumped to the exited states,and then relaxed to energy levels of defect states,afterwards recombined via transition between defect state levels and valence band maximum to emit photons.In addition,the phenomenon of the redshift of PL peak with the increase of the flow rate ratio R may arise from two possible reasons,i.e.the shifting of energy level at the maximum position of density of defect state caused by the transformation of N-Si-O bonding configuration and upward shift of valence band maximum arising from the reduction of optical band gap.关键词
光致发光/a/-SiNx:O薄膜/N-Si/-O键/缺陷态Key words
photoluminescence/a-SiNx∶O film/N-Si-O bond/defect state分类
信息技术与安全科学引用本文复制引用
董恒平,陈坤基,宗波,井娥林,王昊,窦如凤,郭燕,徐骏..非晶掺氧氮化硅薄膜中N-Si-O发光缺陷态的研究[J].南京大学学报（自然科学版）,2017,53(3):392-398,7.基金项目
江苏省高校自然科学研究面上项目(14KJB510014),南京大学固体微结构物理国家重点实验室开放课题基金(M29026),江苏省"青蓝工程" （14KJB510014）
