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采用双极脉冲磁控反应溅射法在不同参数条件下制备了一系列氮化硅薄膜。利用数字式显微镜和紫外-可见光光谱仪研究了沉积薄膜的表面形貌及其光学带隙,利用共焦显微拉曼光谱仪比较了硅衬底、氮化硅薄膜退火前后的拉曼光谱。结果表明,氮气流量对薄膜的光学带隙影响较大,制备的薄膜主要为富硅氮化硅薄膜。原沉积薄膜的拉曼光谱存在明显的非晶硅和单晶硅峰,退火处理后非晶硅峰减弱或消失,表明薄膜出现明显的结晶化;单晶硅峰出现频移现象,表明薄膜中出现硅纳米颗粒,平均尺寸约为6.6 nm。 相似文献
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Yb:YAG晶体中的荧光浓度猝灭现象 总被引:4,自引:0,他引:4
在Yb:YAG晶体中发现浓度猝灭现象,对猝灭机制进行了分析研究,指出退火前晶体的荧光浓度猝灭现象主要由Yb^2+、色心和由此产生的晶格畸变所致高掺杂浓度时痕量稀土杂质离子的存在也将导致浓度猝灭,确定了Yb:YAG晶体中Yb^3+的理想掺杂浓度。 相似文献
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To more in depth understand the doping effects of oxygen on Si Ge alloys, both the micro-structure and properties of O-doped Si Ge(including: bulk,(001) surface, and(110) surface) are calculated by DFT + U method in the present work.The calculated results are as follows.(i) The(110) surface is the main exposing surface of Si Ge, in which O impurity prefers to occupy the surface vacancy sites.(ii) For O interstitial doping on Si Ge(110) surface, the existences of energy states caused by O doping in the band gap not only enhance the infrared light absorption, but also improve the behaviors of photo-generated carriers.(iii) The finding about decreased surface work function of O-doped Si Ge(110) surface can confirm previous experimental observations.(iv) In all cases, O doing mainly induces the electronic structures near the band gap to vary, but is not directly involved in these variations. Therefore, these findings in the present work not only can provide further explanation and analysis for the corresponding underlying mechanism for some of the experimental findings reported in the literature, but also conduce to the development of μc-Si Ge-based solar cells in the future. 相似文献
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采用溶胶-凝胶法合成了用于Nd:Gd3Ga5O12(GGG)透明激光陶瓷的多晶纳米粉体,并利用XRD、SEM、荧光光谱分析对所得的GGG纳米粉体进行了分析。XRD分析结果表明:样品属于体心立方的晶体结构,随着温度的升高,粉体的晶化程度也相应提高,衍射峰强度增强,宽度减小,说明粉体粒径逐渐长大;SEM观察发现,获得了单分散、形状规则、似球形的GGG纳米粉体,且随着烧结温度的提高前驱粉体粒度不断增加。1000℃,12h是形成Nd:GGG纯相的较好的温度和烧结时间;荧光发射的最强峰位于1.06μm处,是Nd^3+的^4I3/2→^4I11/2能级跃迁导致的荧光发射。溶胶-凝胶法制得的Nd:GGG粉体是比较均匀的,粒度较小的,纳米级的晶粒,有利于透明的陶瓷烧强,因此是比较合适的透明陶瓷前驱原料。 相似文献
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采用双极脉冲磁控溅射系统,在不同氧气含量的氩氧混合气体中制备了单层镍-铬金属-电介质复合光谱选择性吸收薄膜。采用X射线衍射仪(XRD)、激光共焦显微拉曼光谱仪、椭偏仪和紫外-可见-近红外分光光度计分别对薄膜的物相结构和光学特性进行了表征。结果表明:实验获得了由金属镍和镍、铬的氧化物(NiO、Cr2O3)组成的复合膜,薄膜对300~1 200 nm波段的太阳光有较强的吸收,而对波长大于1 200 nm的太阳光则吸收较弱,具有良好的光谱选择性,可用作高效太阳光谱选择性吸收涂层。 相似文献