CAJ | 학술논문

利用两种不同激发波长进行Raman测量，研究了低碳含量a-Si1-xCx∶H(～＜20at.%)薄膜的结构特征.采用647.1nm激发时，由于激发光能量接近于各样品的光学带隙，因而在样品中具有较大的穿透深度；而采用488nm激发时，激发光被样品表面强烈吸收.探测深度的变化造成了两种激发下Raman谱出现较大的差异.实验结果表明样品体内存在硅团簇结构，样品的自由表面存在一层高浓度的缺陷层.这两种空间的不均匀性造成了高能激发时Raman谱的TO模频率和半高宽比低能激发时有大的红移和展宽.以上结果证明不同激发波长将造成Raman测量结果的差异.
이용량충불동격발파장진행Raman측량，연구료저탄함량a-Si1-xCx∶H(～＜20at.%)박막적결구특정.채용647.1nm격발시，유우격발광능량접근우각양품적광학대극，인이재양품중구유교대적천투심도；이채용488nm격발시，격발광피양품표면강렬흡수.탐측심도적변화조성료량충격발하Raman보출현교대적차이.실험결과표명양품체내존재규단족결구，양품적자유표면존재일층고농도적결함층.저량충공간적불균균성조성료고능격발시Raman보적TO모빈솔화반고관비저능격발시유대적홍이화전관.이상결과증명불동격발파장장조성Raman측량결과적차이.
The network disorder of a-Si1-xCx∶H films,with carbon concentration below 20at.% has been studied by means of Raman spectroscopy.Two different radiations are employed：one is Kr+ 647.1nm，which is weakly absorbed,with the corresponding energy nearly the same as the optical gaps of these materials;the other is Ar+ 488nm that is strongly absorbed at the free surface，whose corresponding energy is higher than the optical gaps of the materials.Owing to the variations of probed depth attained by two excitation radiations a significant difference is observed in the Raman spectra,which indicates the existence of two kinds of spatially inhomogeneities:a highly disordered thin layer near free surface and inhomogeneities in the bulk.When excited with strongly absorbed radiation,the frequency and width of TO mode have a relatively large redshift and broadening compared with the weakly absorbed one.The above results indicate that different radiation may lead to different Raman results.