【作者】 陈支勇；

【导师】 谢二庆；

【作者基本信息】 兰州大学 ， 凝聚态物理， 2010， 博士

【摘要】 SiCN是一种新颖的硅基光电材料,而稀土掺杂是一种进一步优化SiCN光学性能的有益尝试,我们制备并研究了稀土掺杂与未掺杂SiCN薄膜。(1) SiCxNy薄膜的制备和性质研究利用射频溅射法在Si衬底上制备了SiCxNy薄膜,并利用X-射线衍射(XRD)、红外吸收谱(FTIR)和X-射线光电子谱(XPS)对薄膜的结构、成份及化学键合状态进行了分析。结果表明,室温制备的SiCN薄膜为非晶状态,并形成了Si-C、Si-N和C-N键；通过改变N2/Ar比,衬底沉积温度,溅射功率等参数可以改变薄膜中的Si,C,N三元素的比例。进而改变薄膜的光学等性质。而在高温下(衬底温度为800℃),薄膜中含有SiCxNy的晶体成分,薄膜表面变得粗糙,SiCxNy薄膜具有较好的光致发光性能。(2)SiCN薄膜基电致发光器件的制备和性质研究在P型硅和ITO基底上反应溅射沉积了200nm左右的SiC,,Ny薄膜,并镀上Al电极形成三明治结构,研究了各种N2分压下器件的电学和发光性质研究表明随着N2分量的增加,器件由双向导电变为单向导电进而最后变为绝缘态,而EL现象由双向导通发光变为单向导通发光,最后变为不发光,建立模型解释了这种现象。发现SiCxNy由于其复杂的网络结构,具有很宽的发光包,发光光谱涵盖400～700nm范围。(3)稀土掺杂SiCN薄膜的制备和后处理及发光性质研究分别在N2和NH3气氛下共溅射法制备了样品,发现稀土Tb掺杂样品具有很好的绿光效应。研究了不同温度和气氛环境下退火处理的样品,发现800℃下NH3处理的样品具有最强的肉眼可见的强绿光发射,空气中700。C以下退火的样品呈现强蓝绿光发射,而碳热处理的样品,1250℃下分解为SiC纳米晶和其他团簇,800℃下退火的样品是最适合的退火温度。用XRD, IR, XPS, PL, PLE等研究了样品分解机制和发光的能量传递机理。更多还原

【Abstract】 SiCN is a novel silicon based photoelectric material, Rare earth doped and undoped SiCN films were prepared and investigated.(1) SiCxNy films were prepared on Si substrates by rf sputtering, and the structures, compositions, and chemical bonds were investigated by XRD, FTIR, and XPS. The results have demonstrated that the room-temperature deposited SiCN films were amorphous, containing a network of Si-C, Si-N, and C-N bonds. The ratio of constituents of the three elements (Si, C, and N) in the films can be tuned by the partial pressure ratios of N2/Ar, the substrate temperatures, and sputtering powers, and this type of change in the compositions change the optical properties of thin films. While, when the temperature increase up to 800℃, the films will contain some crystalling components of SiCxNy with a coarse surface. The films show a good properties of electroluminescence (EL).(2) The preparation and properties of of SiCN-film-based EL devices were investigated by using a ITO/SiCN/Al sandwich structure. The effect of the partial pressure ratios of N2 on the electronic and luminescent properties of the devices were disscused. The results have demostrated that the devices changed from bidirectional to unilateral, even Insulating, accompanying with the EL changing from a bidirectional luminscence to an unilateral one, finally a non-luminous one. A model were proposed to illuminestrate this phenomenon. The investigation demostrated that SiCxNy shows a broad luminescent band ranging from 400-700nm due to the Complex network structure.(3) The preparation, post-treatment, and photoluminescence (PL) properties of rare earth doped SiCN films were investigated. Two types of Tb-doped SiCN films were deposited by cosputtering of Tb flake and SiC target under N2 and NH3 ambience. The prepared Tb-doped samples show a good green light emission. The annealing treatment under different temperatures and gas ambiences have indicated that the samples treated under NH3 ambience at 800℃and show the strongest visible green light emission, and the samples annealed in air at only 700℃show the strongest ones.However, the samples treated under carbothermal ambience at 800℃show the best PL behaviour. Once the annealing temperature increase up to 1250℃, the films will decomposited into SiC nanocrystal and other nanoclusters. Furthermore, the mechanism of the decomposition of the samples and energy transfer of PL were discussed by using XRD, IR, XPS, PL, and PLE.更多还原