纳米硅粒子的表面氧化及其光致发光特性

采用射频等离子体增强化学气相沉积技术制备了纳米晶硅粒子,并对其溶液发光的稳态和瞬态特性进行了研究.稳态光致发光结果显示,新制备的纳米硅粉体表现为峰值位于440 nm附近的蓝色发光,经长时间氧化后,该波段发光强度显著增强,并且出现另一峰值位于750 nm附近的红色发光带.不同波长激发和时间分辨光致发光谱的分析表明,纳米硅...     

Surface plasmon enhanced photoluminescence in amorphous silicon carbide films by adjusting Ag island film sizes

Ag island films with different sizes are deposited on hydrogenated amorphous silicon carbide (α-SiC:H) films, and the influences of Ag island films on the optical properties of the α-SiC:H films are investigated. Atomic force microscope images show that Ag nanoislands are formed after Ag coating, and the size of the Ag islands increases with increasing Ag deposition time. The extinction spectra indicate that two resonance absorption peaks which correspond to out-of-plane and in-plane surface plasmon modes of the Ag island films are obtained, and the resonance peak shifts toward longer wavelength with increasing Ag island size. The photoluminescence (PL) enhancement or quenching depends on the size of Ag islands, and PL enhancement by 1.6 times on the main PL band is obtained when the sputtering time is 10 min. Analyses show that the influence of surface plasmons on the PL of α-SiC:H is determined by the competition between the scattering and absorption of Ag islands, and PL enhancement is obtained when scattering is the main interaction between the Ag islands and incident light.     

柔性有机/无机杂化钙钛矿太阳电池研究进展

柔性太阳电池具有重量轻、可卷对卷连续生产、可卷曲、不易破碎、便于携带和可穿戴等特点，可在多种领域为人们提供电力，具有非常广泛的应用前景。近年来，在基于刚性衬底的有机/无机杂化钙钛矿太阳电池（PSC）展示了出色的功率转换效率之后，柔性PSC研究也受到了人们的广泛关注。目前，柔性PSC的转换效率已经达到了18.1%。本文介绍了近年来柔性PSC领域的相关研究工作，综述了已应用于柔性PSC的柔性基底、透明电极和界面传输层等关键材料近来的发展，并探讨了这些材料应用于柔性PSC时的优势和面临的主要问题，最后对柔性PSC未来的发展进行了展望。     

氢化纳米硅薄膜中氢的键合特征及其能带结构分析

对氢化纳米硅薄膜中氢的键合特征和薄膜能带结构之间的关系进行了研究.所用样品采用螺 旋波等离子体化学气相沉积技术制备，利用Raman散射、红外吸收和光学吸收技术对薄膜的 微观结构、氢的键合特征以及能带结构特性进行了分析.Raman结果显示不同衬底温度下所生 长薄膜的微观结构存在显著差异，从非晶硅到纳米晶硅转化的衬底温度阈值为200℃.薄膜中 氢的键合特征与薄膜的能带结构密切相关.氢化非晶硅薄膜具有较高的氢含量，因键合氢引 起的价带化学位移和低衬底温度决定的结构无序性，使薄膜呈现较大的光学带隙和带尾宽度 .升 关键词： 氢化纳米硅 螺旋波等离子体 能带结构     

热退火诱导纳米银膜形貌变化对表面等离激元共振特性的影响

采用磁控溅射技术制备并通过不同温度的快速热退火得到了不同表面形貌的纳米银膜。利用XRD,SEM和紫外-可见-近红外透射光谱等技术研究了纳米银膜的结构、表面形貌与光学性质。实验结果表明,随着退火温度的升高,银膜开口面积分数、银岛(纳米粒子)间距增大,长宽比减小,银岛由各向异性的蠕虫状变成各向同性的纳米球;表面等离激元共振带发生连续的蓝移,半高宽变窄。分析表明,纳米银膜的表面等离激元共振特性可以通过热退火诱导的表面形貌变化实现调整。     

非晶氧化硅薄膜带尾发光特性

采用等离子体增强化学气相沉积技术,通过改变CO2流量制备了不同氧含量的非晶氧化硅薄膜。利用紫外可见吸收谱、傅里叶红外吸收谱和稳态/瞬态光致发光谱等技术研究了薄膜的微观结构和光学特性。实验结果表明,随着氧含量的增加,薄膜的带隙增大,光致发光强度增加、峰值朝高能方向移动、光谱半峰全宽展宽。时间分辨光谱显示薄膜发光峰值处的衰减时间随氧含量的增加从6.2ns单调增加到21ns,而同一样品的发光寿命随发射波长能量增加而减小。综合分析光学吸收、发射及发光衰减特性表明,薄膜的发光机制主要归结为非晶材料带尾态之间的辐射复合。     

Structural and band tail state photoluminescence properties of amorphous SiC films with different amounts of carbon

Amorphous silicon carbide films are deposited by the plasma enhanced chemical vapour deposition technique,and optical emissions from the near-infrared to the visible are obtained.The optical band gap of the films increases from 1.91 eV to 2.92 eV by increasing the carbon content,and the photoluminescence(PL) peak shifts from 1.51 eV to 2.16 eV.The band tail state PL mechanism is confirmed by analysing the optical band gap,PL intensity,the Stocks shift of the PL,and the Urbach energy of the film.The PL decay times of the samples are in the nanosecond scale,and the dependence of the PL lifetime on the emission energy also supports that the optical emission is related to the radiative recombination in the band tail state.     

螺旋波等离子体化学气相沉积纳米硅薄膜的光学发射谱研究

利用光学发射谱技术对螺旋波等离子体化学气相沉积纳米硅薄膜的等离子体内活性粒子的光发射特征进行了原位测量.研究了薄膜沉积过程中各实验参量对活性基团SiH^*， H^β以及H^α的发射谱强度的影响.实验结果表明，静态磁场的加入可显著提高反应气体 的解离效率 ；适当的氢稀释可以提高氢活性粒子的浓度，而过高的氢稀释比将使含硅活性基团浓度显著 减小；提高射频馈入功率整体上可以使各活性粒子的浓度增加，并有利于提高到达衬底表面 氢活性粒子的相对比例.结合螺旋波等离子体色散关系和等离子体特点对以上结果进行了分 析.该结果为螺旋波等离子体沉积纳米硅薄膜过程的理解及制备工艺参数的调整提供了基础 数据. 关键词： 光学发射谱 螺旋波等离子体化学气相沉积 纳米硅薄膜     

Electronic structure and defect states of transition films from amorphous to microcrystalline silicon studied by surface photovoltage spectroscopy

In this paper, surface photovoltage spectroscopy （SPS） is used to determine the electronic structure of the hydrogenated transition Si films. All samples are prepared by using helicon wave plasma-enhanced chemical vapour deposition technique, the films exhibit a transition from the amorphous phase to the microcrystalline phase with increasing temperature. The film deposited at lower substrate temperature has the amorphous-like electronic structure with two types of dominant defect states corresponding to the occupied Si dangling bond states （D^0/D^-） and the empty Si dangling states （D＋）. At higher substrate temperature, the crystallinity of the deposited films increases, while their band gap energy decreases. Meanwhile, two types of additional defect states is incorporate into the films as compared with the amorphous counterpart, which is attributed to the interface defect states between the microcrystalline Si grains and the amorphous matrix. The relative SPS intensity of these two kinds of defect states in samples deposited above 300℃ increases first and decreases afterwards, which may be interpreted as a result of the competition between hydrogen release and crystalline grain size increment with increasing substrate temperature.