多孔硅的氢化、氧化与光致发光

对于刚阳极氧化完的，阳极氧化后紧接着在Ｈ２Ｏ２中光照处理的及长期存放（１０个月）的三种多孔硅样品进行了持续激光照射，不断监视它们的光致发光（ＰＬ）与富利埃变换红外（ＦＴＩＲ）吸收光谱，并在最后对它们作了Ｘ射线光电子能谱（ＸＰＳ）测量，以确定它们所含氧化硅的情况．得出如下几条结论：（１）氢对多孔硅表面的钝化是不稳定的．（２）Ｓｉ—Ｈ键不是发光所必须的．（３）氧对多孔硅表面的钝化是稳定的，纳米硅周围氧化层的存在及其特性对于稳定的多孔硅可见光发射是至关重要的．对激光照射下多孔硅发光的退化提出了新的解释．     

钝化多孔硅的光致发光

选用含有胺基的正丁胺(CH3CH2CH2CH2-NH2)作碳源,采用射频辉光放电法制备碳膜对多孔硅进行碳膜钝化,其光致发光谱和存放实验表明:正丁胺对多孔硅进行钝化是一种十分有效的多孔硅后处理途径.研究了钝化多孔硅的光致发光谱随钝化温度和钝化时间的变化关系,其结果显示:通过调节钝化条件可实现钝化多孔硅最大的发光效率和所需要的发光颜色.     

钝化多孔硅的光致发光

选用含有胺基的正丁胺(CH3CH2CH2CH2-NH2)作碳源,采用射频辉光放电法制备碳膜对多孔硅进行碳膜钝化,其光致发光谱和存放实验表明:正丁胺对多孔硅进行钝化是一种十分有效的多孔硅后处理途径.研究了钝化多孔硅的光致发光谱随钝化温度和钝化时间的变化关系,其结果显示:通过调节钝化条件可实现钝化多孔硅最大的发光效率和所需要的发光颜色.     

钝化多孔硅的光致发光

选用含有胺基的正丁胺 (CH3CH2 CH2 CH2 - NH2 )作碳源 ,采用射频辉光放电法制备碳膜对多孔硅进行碳膜钝化 ,其光致发光谱和存放实验表明 :正丁胺对多孔硅进行钝化是一种十分有效的多孔硅后处理途径 .研究了钝化多孔硅的光致发光谱随钝化温度和钝化时间的变化关系 ,其结果显示 :通过调节钝化条件可实现钝化多孔硅最大的发光效率和所需要的发光颜色     

激光脉冲能量对类金刚石薄膜及其红外光学特性的影响

为了研究在氮气中激光的脉冲能量对类金刚石薄膜的微结构组成、表面形貌和红外光学特性的影响,在KrF准分子脉冲激光沉积(PLD)类金刚石薄膜的实验中,在沉积腔中充入10-1Pa氮气并保持其他实验参数不变,脉冲能量分别取120 mJ和150 mJ来沉积类金刚石薄膜。用拉曼光谱仪和X射线光电子能谱仪(XPS)对类金刚石薄膜的微结构与组成进行检测分析;用原子力显微镜(AFM)对薄膜的表面形貌进行检测分析;用傅里叶变换红外光谱仪对类金刚石薄膜和硅衬底的红外光透射谱进行检测分析。实验结果表明,脉冲能量从120 mJ增加到150 mJ导致类金刚石薄膜中的氮含量和sp3键含量增加,C-O,C=O和O的含量减少,石墨晶粒的数量减少、尺寸变小,薄膜表面的粗糙度显著降低。同时,脉冲能量增加导致类金刚石薄膜对红外光的增透作用减弱,增透范围变窄。     

生长温度对类金刚石膜结构和发光性质的影响

使用脉冲激光沉积技术制备了系列无氢类金刚石薄膜,测量了样品的Raman光谱、光吸收光谱和光致发光光谱,研究了薄膜结构和光致发光性质与制备条件的依赖关系。结果表明,这种薄膜是由少量sp2键和大量sp3键组成的非晶碳膜。薄膜的光学带隙在1.68~2.46eV,发光在可见光区呈宽带结构。生长温度能够对类金刚石薄膜的结构和发光性质产生较大影响。当生长温度从室温升高至400℃时,sp2团簇的变大使C原子的有序度增强,从而导致薄膜的光学带隙变窄,发光峰红移且半高宽变小。     

铁钝化多孔硅的水热制备法及其光致发光特性

利用水热技术原位制备出铁钝化多孔硅样品,并对其发光特性进行了测试。样品具有较强的光致发光强度,而且在室温空气存放过程中其发光强度不发生衰减,发光峰位不发生蓝移。上述发光特性归因于样品表面形成的良好铁钝化。     

多孔硅衬底微波CVD金刚石薄膜的制备及其场电子发射

研究了多孔硅衬底微波CVD金刚石薄膜的制备工艺及其场电子发射特性.以多孔硅作为生长金刚石突起阵列的模板,生长出带多微尖的微晶金刚石晶粒,使场电子发射阈值下降(＜1V/μm),发射电流增大(＞90mA/cm2),场发射性能稳定,并对这种场发射特性做出了理论解释.     

掺氮对类金刚石薄膜场发射的影响

利用脉冲激光沉积技术制备出了掺氮和未掺氮的类金刚石薄膜。采用X射线衍射仪、喇曼光谱仪、扫描电镜观察了掺氮和未掺氮类金刚石薄膜的微结构和表面形貌。场发射实验表明,掺氮降低了类金刚石薄膜的阈值电场,提高了发射电流密度。     

多孔硅衬底微波CVD金刚石薄膜的制备及其场电子发射

研究了多孔硅衬底微波CVD金刚石薄膜的制备工艺及其场电子发射特性.以多孔硅作为生长金刚石突起阵列的模板,生长出带多微尖的微晶金刚石晶粒,使场电子发射阈值下降(<1V/ μm) ,发射电流增大(>90 m A/ cm2 ) ,场发射性能稳定,并对这种场发射特性做出了理论解释.     

PECVD法制备类金刚石薄膜结构和表面形貌分析

以CH4为碳源,Ar气为载气,采用等离子体增强化学气相沉积法(PECVD)在硅(100)衬底上制备了类金刚石(DLC)薄膜。利用拉曼(Raman)光谱仪与原子力显微镜(AFM)对其结构与表面形貌进行了表征。结果表明:所制备的DLC薄膜是含sp3和sp2混合键的非晶态碳膜,其表面均匀、光滑、致密;且随着射频功率的提高,薄膜的平均晶粒直径由8.0nm降为4.2nm,粗糙度由2.2nm减为0.9nm。     

Visible photoluminescence from ZnO/diamond-like carbon thin films

ZnO/diamond-like carbon (DLC) thin films are deposited by pulsed laser deposition (PLD) on Si (111) wafer. Visible room-temperature photoluminescence (PL) is observed from ZnO/DLC thin films by fluorescence spectrophotometer. The Gaussian curve fitting of PL spectra reveals that the broadband visible emission contains three components with λ=508 nm, 554 nm and 698 nm. The origin and possible mechanism of the visible PL are discussed, and they can be attributed to the PL recombination of ZnO and DLC thin films.     

Diamond Like Carbon Film Deposited on Porous Silicon as Passivation Coating

By depositing diamond like carbon(DLC)film with radio frequency plasma chemical vapor deposition(RFPCVD)method,a new surface passivation technique for photoluminescence porous silicon(PS)has been studied.The surface microstructure and photoelectric properties of both porous silicon and DLC coated PS have been analyzed by using AFM,FTIR and PL spectrometers.The results show the DLC film with dense and homogenous nanometer grains can be deposited on the PS used as passivation coating as it can terminate oxide reaction on the surface of the PS.Furthermore,certain ratio of hydrogen existed in the DLC film can be improved to form hydride species on the DLC/PS interface as the centers of the luminescence so that the DLC coating is of benefit not only to the passivation of the PS but also to the improvement of its luminescent intensity.     

Plasma deposition of inorganic silicon containing films

Amorphous films containing silicon in combination with nitrogen, oxygen, carbon and hydrogen, comprise a wide range of potentially useful materials for the construction of microelectronic circuits. Glow discharge induced deposition is a viable alternative to the other more common chemical and physical deposition methods. Silane (SiH₄) reacted with different ratios of nitriding or oxidizing agents in a glow discharge produce films of varying composition and properties. At low discharge power film density is primarily a function of surface temperature. Nitride films grown at low temperature and low power density contain substantial amounts of Si-H and N-H bonds, some of which can be removed by high temperature annealing. Many film properties can be measured. Correlation of some of these with annealing provides a simple model for assigning a figure of merit to material.     

掺N类金刚石薄膜的制备及微观结构分析

采用直流磁控溅射法,在光学玻璃衬底上沉积类金刚石(DLC)和掺N类金刚石薄膜(DLC:N)。用喇曼光谱、X射线光电子能谱(XPS)、傅里叶红外光谱(FTIR)等研究分析了所制备薄膜的微观结构。喇曼光谱的结果表明,掺N类金刚石膜仍具有典型的类金刚石膜结构,在类金刚石薄膜中掺N不仅有助于提高膜中sp3/sp2的比例,而且还能阻止sp2键向石墨相的转化,稳定并优化薄膜的类金刚石属性。FTIR表明,薄膜中N与C原子形成了C—N、CN及C≡N等键合方式。XPS谱表明,掺N类金刚石膜中除了C和N元素外,还出现了少量的O元素,而C1s和N1s的解谱显示,掺N后的类金刚石膜中的C、N结合能发生了明显的移动,由计算得出薄膜中N的含量为13.5%。薄膜的表面形貌图(AFM)表明,在类金刚石薄膜中掺N能够改善其表面形貌。     

Surface of porous silicon under hydrophilization and hydrolytic degradation

Analysis of the IR absorption spectra is used to trace changes in the chemical composition of surface layers of mesoporous silicon crystals during the course of their hydrophilization via oxidation in hydrogen-peroxide solutions and as a result of indirect, by intermediate bromination, and direct nucleophilic substitution of bound hydrogen with a hydroxyl. The spontaneous process of atomic rearrangement with the transfer of oxygen atoms from adsorbed OH groups to lower-lying atomic layers of the crystalline skeleton, which yields Si-H bonds on its surface: -Si-Si-OH→-Si-O-Si-H, is revealed. The sequence of elementary processes that facilitate the hydrolytic degradation of porous silicon in weakly alkaline media is considered. The role played by the deformation of chemical bonds in a porous crystal in promoting the hydrolysis of silicon is noted. It is shown that the surface modification of porous silicon via bromination and subsequent treatment in water makes it possible to substantially increase the rate of its hydrolytic degradation in weakly alkaline solutions that are similar in pH values to biological fluids.     

Optical properties of ZnO thin films grown on diamond-like carbon by pulsed laser deposition

ZnO/diamond-like carbon(DLC)thin films are deposited by pulsed laser deposition(PLD),and the room-temperature photoluminescence(PL)is investigated.Using a fluorescence spectrophotometer,we obtain the PL spectra of DLC/Si and ZnO/Si thin films deposited at different substrate temperatures.The ZnO/DLC thin films show a broadband emission almost containing the entire visible spectrum.The Gaussian fitting curves of PL spectra reveal that the visible emission of ZnO/DLC thin films consists of three peaks centered at 381 nm,526 nm and 682 nm,which are attributed to the radiative recombination of ZnO and DLC,respectively.The Commission International de l,Eclairage(CIE)1931(x,y)chromaticity space of ZnO/DLC thin films indicates that the visible PL spectrum is very close to the standard white-light region.     

氮气压强对脉冲激光沉积类金刚石薄膜和红外光学特性的影响

为了研究氮气压强对脉冲激光沉积(PLD)类金刚石(DLC)薄膜和红外光学特性的影响,在脉冲激光沉积类金刚石薄膜的实验过程中,把沉积腔抽真空到10-5Pa,再在沉积腔中分别充入10-3、10-2和10-1Pa的氮气来沉积类金刚石薄膜。用拉曼光谱仪和X射线光电子能谱仪(XPS)对类金刚石薄膜的微结构与组成进行检测分析;用原子力显微镜(AFM)对薄膜的表面形貌进行检测分析;用傅里叶变换红外光谱仪(FTIR)对类金刚石薄膜的红外光透射谱进行检测分析。实验结果表明,沉积腔中的氮气压强从10-3Pa增加到10-1Pa时,类金刚石薄膜中sp3键含量增加;C-O和C=O含量减少;石墨晶粒尺寸减小;薄膜表面粗糙度显著增大。与此同时,氮气压强增加还导致类金刚石薄膜对红外光的增透作用减弱、增透范围变窄。     

磁过滤阴极真空弧沉积薄膜研究

采用磁过滤阴极真空弧沉积技术对从弧源引起离子束中的大颗粒进行过滤后,在硅和聚合物表面进行离子注入和低能离子束沉积,可获得特性优异的沉积金属膜、超硬膜（类金刚石,CN膜）、陶瓷膜（TiN,TiC）等。电子显微镜观察表明,大颗粒已被过滤,表面结构致密,由于先进行离子注入,在基体表现预先形成了过滤层,从而改善了沉积膜的粘合特性,膜与基体的粘合特性有了明显提高。测量结果表明,沉积膜的硬度、抗磨损和抗腐蚀特性均有了明显提高。非晶金刚石薄膜表面硬度可达到56GPa。     

Enhanced crystallization and improved reliability for low-temperature-processed poly-Si TFTs with NH/sub 3/-plasma pretreatment before crystallization

NH/sub 3/-plasma pretreatment before crystallization was performed for the first time on low-temperature-processed poly-Si thin-film transistors (TFTs). TFTs after pretreatment can significantly reduce the thermal crystallization time of amorphous silicon from 24 to 4 h. The pretreatment can also improve device performance and hot-carrier resistivity. It was attributed to the defect-state passivation of nitrogen that is piled-up near the poly-Si film surface, which helps to terminate the dangling bonds in poly-Si thin film in place of weaker Si-H and/or Si-Si bonds. This new scheme provides a simple and effective method to decrease /spl alpha/-Si film crystallization time and simultaneously improve device performance and reliability.