双离子束溅射法制备SiOxNy薄膜的结构与发光

本文采用双离子束溅射沉积法制备了SiOxNy复合薄膜,XRD、TEM测试表明薄膜呈非晶态,FTIR及XPS测试表明薄膜成分由Si、O、N组成,在室温下可观察到样品有400 nm（紫光）、470 nm（蓝光）的光致发光.根据测试分析研究了SiOxNy薄膜的可能的发光机理：470 nm处发光峰为来自于硅基薄膜中中性氧空位缺陷（O3≡Si-Si≡O3）,是由于氧原子配位的二价硅的单态-单态之间的跃迁所致,其发光强度随退火温度的升高而变化,800℃时最大,高于800℃时慢慢减弱;400 nm发光峰的发射与薄膜中的Si、O、N所形成的结构有关,它可能来自于Si、O、N结构所形成的发光中心,该峰位的强度随退火温度的升高而增强.     

退火对两种硅基薄膜的结构及发光影响

采用双离子束共溅射沉积方法制备了两种复合硅基薄膜SiOxCy和SiOxNy薄膜,对两种薄膜进行后退火处理,并分别对样品进行PL、FTIR、XPS谱测试分析,比较退火前后的发光及结构的变化。两种样品的光致发光测试谱(PL)表明:退火前后都有两个发光峰位-都存在470nm的发光峰位,它来自于硅基薄膜中中性氧空位缺陷(O3≡Si-Si≡O3),是由于氧原子配位的二价硅的单态-单态之间的跃迁所致,其发光强度随退火温度的升高而变化。进一步的FTIR和XPS的测试谱表明另外一个发光峰位420nm(SiOxCy薄膜)和400nm(SiOxNy薄膜)分别来自于掺杂杂质(C和N)与硅基薄膜中的Si、O组成的复合结构。而两种样品经过退火处理后掺杂所引起的发光峰位强度随退火温度的升高而增强,说明退火温度的升高有利于发光机制的形成。     

空气环境下退火温度对连续SiC自由膜结构与发光特性的影响EI北大核心

采用熔融纺膜与先驱体转化法相结合制备出连续SiC自由薄膜,研究薄膜在1300,1400,1500℃温度下空气退火处理的氧化行为,以及退火温度对薄膜微观结构、光致发光特性(PL)、硬度和电阻率的影响。结果表明,SiC薄膜在1300℃具有较佳的抗氧化和发光特性,随着退火温度的升高,薄膜的抗氧化和发光特性略有降低,薄膜中无定型SiOxCy减少,-βSiC晶粒长大及游离碳增多,薄膜表面硬度与电阻率下降,表面惰性致密氧化层的生成保护阻挡氧扩散,从而有效减缓薄膜进一步被氧化。     

退火温度对ZnO:Al透明导电薄膜结构和性能的影响

采用溶胶-凝胶法(sol-gel)在普通载玻片上制备了ZnO∶Al薄膜,在200～600℃下退火.利用XRD、紫外-可见光-近红外分光光度计和电阻测试仪等分析方法研究了不同退火温度对薄膜结构和光电性能的影响.结果表明,退火温度在300℃以上,薄膜开始结晶,400℃以上,薄膜出现明显结晶,且沿(002)方向择优取向,随着退火温度升高,(002)峰的强度逐渐增强,晶粒尺寸逐渐增加;薄膜在可见光范围内的透过率均＞85%以上,退火温度高的薄膜在可见光范围内的透过率明显提高,光学带隙在3.32～3.54eV,且随着温度的升高而降低;薄膜的电阻率随退火温度的增高而有所降低,但是仍较高,在103俜cm量级.     

NiFeCr/NiFe/MgO/Ta薄膜制备及热处理研究

采用磁控溅射制备了NiFeCr(4.5nm)/NiFe(10nm)/MgO(4.0nm)/Ta(5.0nm)薄膜,并对薄膜进行真空磁场退火。退火后薄膜磁电阻变化率显著提高,400℃退火后达到3.02%,之后随着退火温度的升高,磁电阻变化率下降。XRD结果表明,薄膜不仅具有很强的NiFe(111)织构,同时还出现了MgO的(111)衍射峰。随退火温度的升高,MgO(111)衍射峰的强度有所降低。     

非晶SiOx:C薄膜的发光特性研究

采用双离子束溅射法制备了SiOx:C非晶薄膜,在室温下可观察到薄膜样品有强的420nm(紫光)、470nm(蓝绿光)的光致发光(PL).分别对样品在不同温度下退火后,PL测试显示随着退火温度的升高420nm处的峰带逐渐增强变为强的发光峰;470nm处的发光峰位来自于硅基薄膜中富硅引起的中性氧空位缺陷(O3≡Si-Si≡O3),是由与氧原子配位的二价硅的单态-单态之间的跃迁所致;420nm范围的峰带可能来自于薄膜中由C单质、以及Si、O、C三者组成的一个复杂结构.     

辐射变色薄膜剂量计的退火效应

制备了一批辐射变色薄膜,利用紫外线辐照该薄膜,辐照后薄膜由无色变为蓝色,并在670nm处出现一吸收峰,吸收峰的吸光度对辐照剂量有良好的线性响应关系。对辐照后的薄膜进行了退火实验,当温度升高到45℃后,出现一新的吸收峰(545nm),随着温度进一步升高670nm峰逐渐消失,545nm峰逐渐升高。当温度达到110℃时,670nm峰完全消失,545nm峰达到稳定,薄膜也相应地由蓝色变为粉红色。薄膜颜色的变化主要是由于其内部分子结构发生了变化:由碳碳三键共轭(无色)变为辐照后的碳碳三键和碳碳双键不在一个平面内的共轭(蓝),最后变为退火后的碳碳三键和碳碳双键在一个平面内的共轭(粉红)。进一步的红外光谱分析也证实了对薄膜结构变化的解释。     

不同生长温度下Zn1-xSbxO薄膜的结构与发光性能研究

采用固相反应法制备了不同比例的Sb掺杂ZnO靶材,并用脉冲激光沉积(PLD)法在Si(100)基底上制备了Zn_1-xSb_xO薄膜。通过XRD、光致发光(PL)谱对所制薄膜进行了结构表征和性能分析,探讨了不同Sb掺杂量和不同生长温度对薄膜结晶质量和发光性能的影响。结果表明：对比纯ZnO的PL谱发现ZnSbO薄膜出现了紫外峰,且随着Sb浓度的增加,所有发光峰的强度相对增大;针对Zn_0.98Sb_0.02O薄膜,不同的基底生长温度改变了薄膜的紫外和蓝光发射强度,500℃下薄膜具有最好的结晶质量和最强的发光峰;对于500℃下生长的Zn_0.98Sb_0.02O薄膜,当激发光源波长从325nm变化到300nm,峰位红移,而且紫外峰与蓝光锋强度比由1∶3变为12∶1。据此,可以通过改变Sb掺杂量、生长温度和激发光源波长,从而制备出不同波段、不同强度的发光器件。     

掺钼氧化锌薄膜的发光特性

使用磁控溅射法在石英基底上制备钼掺杂氧化锌薄膜.扫描电镜结果表明薄膜由晶粒大小为40～ 80 nm范围内的颗粒组成,薄膜具有六方纤锌矿型结构且沿c轴择优取向生长.在可见光范围(400～760 nm)内所有薄膜的平均光透射率超过90％.退火薄膜的光致发光(PL)光谱表明,退火处理对发光峰的位置有很大影响,随着退火温度的增加,发光峰位置从380 nm红移至400nm或从470 nm红移至525 nm.此外,钼掺杂对退火薄膜PL光谱的强度影响很大.我们认为,薄膜中缺陷浓度的变化是导致发光峰红移的主要原因,讨论了PL谱中不同的可见光的发光机制.     

锌膜氧化制备氧化锌薄膜的紫光发射

通过锌膜在金属锌熔点(419℃)以上温度和50Pa的氧气压力下退火氧化的方法制备ZnO薄膜,研究了退火温度对ZnO薄膜组织结构及发光性能的影响.ZnO薄膜的室温光致发光谱是由发光中心在424nm处的单一紫光组成.随着退火温度的升高,紫光的强度增加,当温度超过600℃时紫光的强度反而降低.在50Pa氧气压力下,紫光的发射归因于电子从价带到锌间隙原子(Zni)缺陷之间的跃迁.     

Effect of annealing temperature and composition on photoluminescence properties of magnetron sputtered SiCN films

Silicon carbonitride (SiCN) films were prepared by means of reactive magnetron sputtering of a sintered SiC target on n-type Si (1 0 0) substrates in the reactant gas of nitrogen, and then the films were respectively annealed at 600, 800 and 1100 °C for 5 min in nitrogen ambient. The films were characterized by energy dispersive spectrometer, X-ray diffraction, Fourier transform infrared spectroscopy and photoluminescence (PL) spectrophotometry. Intense PL peaks at 370, 400 and 440 nm were observed at room temperature. The results show that annealing temperature and composition play an important role in the structures and PL properties of the films. The annealing temperature of 600 °C favors the formation of the SiC (1 0 9) crystal in the SiCN films, and results in a maximal PL peak. The intensity of the 440 nm PL peak can be improved by increasing the abundance of the Si-C bond.     

SiNx薄膜中硅纳米粒子的制备及表征

通过等离子增强化学气相沉积(PECVD)法, 以氨气和硅烷为反应气体, P型单晶硅和石英为衬底, 低温下(200℃)制备了含硅纳米粒子的非化学计量比氮化硅(SiN_x)薄膜. 经高温(范围500~950℃)退火处理优化了薄膜结构. 室温下测试了不同温度退火后含硅纳米粒子SiN_x薄膜的拉曼(Raman)光谱、光致发光(PL)光谱及傅立叶变换红外吸收(FTIR)光谱, 对薄膜材料的结构特性、发光特性及其键合特性进行了分析. Raman光谱表明. SiN_x薄膜内的硅纳米粒子为非晶结构. PL光谱显示两条与硅纳米粒子相关的光谱带, 随退火温度的升高此两光谱带峰位移动方向相同. 当退火温度低于800℃时, PL光谱峰位随退火温度的升高而蓝移. 当退火温度高于800℃时, PL光谱峰位随退火温度的升高而红移. 通过SiNx薄膜的三种光谱分析发现薄膜的光致发光源于硅纳米粒子的量子限制效应. 这些结果对硅纳米粒子制备工艺优化和硅纳米粒子光电器件的应用有重要意义.     

[101]取向Li掺杂ZnO薄膜光学性能的研究

采用射频磁控溅射法在玻璃衬底上制备了[101]取向的Li:ZnO薄膜, 研究了该薄膜的光学性能随热处理温度变化的规律. 结果表明, 399nm的发光峰是由Li的杂质能级引起; 与[002]取向的薄膜相比, 未经热处理的[101]薄膜其光学带隙大, 且出现了380nm附近的带边发射(NBE) 峰; 在560～580℃热处理下, 其晶胞变小、光学带隙变窄、360nm 左右的带间发光峰红移; 当热处理温度升至610℃时, 薄膜中再次出现380nm的NBE峰.     

Photoluminescence from RF sputtered SiCBN thin films

Silicon carbon boron nitride (SiCBN) thin films were synthesized by reactive co-sputtering of silicon carbide (SiC) and boron nitride (BN) targets. As-deposited samples show distinct photoluminescence (PL) peaks at 465, 483 and 497 nm. The films were annealed in dry oxygen ambient at different temperatures to investigate the effect of annealing on film properties. Subsequent measurements on the annealed samples show diminished PL peak intensities. X-ray diffraction analysis shows that the as-deposited films are amorphous in nature and there is no change in the microstructure even after high temperature annealing. Surface characterization of the films by X-ray photoelectron spectroscopy reveals change in chemical composition at different annealing temperatures. Carbon concentrations in the films are sensitive to annealing temperatures and could cause the change in photoluminescence properties.     

The structure and photoluminescence properties of ZnO/SiC multilayer film on Si substrate

ZnO/SiC multilayer film has been fabricated on a Si (111) substrate with a silicon carbide (SiC) buffer layer using the RF (radio frequency)-magnetron technique with targets of a ceramic polycrystalline zinc oxide (ZnO) and a composite target of pure C plate with attached Si chips on the surface. The as-deposited films were annealed at a temperature range of 600–1000°C under nitrogen atmosphere. The structure and photoluminescence (PL) properties of the samples were measured using X-ray diffractometry (XRD), Fourier transform infrared (FTIR) spectroscopy and PL spectrophotometry. By increasing the annealing temperature to 800°C, it is found that all the ZnO peaks have the strongest intensities, and the crystallinity of ZnO is more consistent on the SiC buffer layer. Further increase of the annealing temperature allows the ZnO and SiC layers to penetrate one another, which makes the interface between ZnO and SiC layer become more and more complicated, thus reduces the crystallinities of ZnO and SiC. The PL properties of a ZnO/SiC multilayer are investigated in detail. It is discovered that the PL intensities of these bands reach their maximum after being annealed at 800°C. The PL peaks shift with an increase in the annealing temperature, which is due to the ZnO and SiC layers penetrating reciprocally. This makes the interface more impacted and complicated, which induces band structure deformation resulting from lattice deformation.     

[100]取向Al-Ti共掺杂ZnO薄膜的制备与光电性能研究

采用常压固相烧结法制备了Al-Ti共掺ZnO靶材, 采用射频磁控溅射技术及真空退火工艺, 在普通玻璃衬底上制备了具有[100]取向Al-Ti共掺杂ZnO薄膜(ZATO). 采用X射线衍射(XRD)、扫描电子显微镜(SEM)对ZATO薄膜的生长机理、显微结构、形貌进行了测试分析, 用四探针测试仪、紫外-可见分光光度计及荧光光谱仪对ZATO薄膜的光电性能进行了测试分析. 结果表明, ZATO薄膜经500℃保温3h退火后, 择优取向由(002)向(100)方向转变; 此时, 衍射谱上还观察到超点阵衍射线条. [100]取向ZATO薄膜的光学带隙从退火前的3.29降至2.86, 平均可见光透过率从90%降至70%, 表现为一般的透过性; 而电阻率则从1.89×10^-2Ω·cm降至1.25×10^-3Ω·cm, 呈现较好的导电性. 薄膜中均出现了380nm附近的带边发射(NBE)峰以及410、564nm的深能级发射峰, 且经500℃保温3h退火后, 这些峰的位置并未改变, 但峰强均明显减弱. 对上述实验机理进行了分析讨论.     

Al2O3薄膜的发光性能及其结构研究

以高纯铝为靶材,在不同氧氩比例下,采用直流反应磁控溅射法制备了Al2O3薄膜。用F-4500型荧光分光光度计测量其荧光光谱,观察到416 nm和438 nm处的光致发光发射谱（PL）,是由于氧空位充当的色心所致,且随着氧氩比例的增加,峰的位置基本不变,强度先上升后下降,这是由于氧氩比例的改变导致氧空位浓度变化引起的。通过对未退火及不同温度退火样品的XRD分析发现：室温沉积的Al2O3薄膜为非晶态,400℃退火开始有晶体出现,且退火温度越高,结晶性能越好。     

Optical characterization of ZnO thin films deposited by Sol-gel method

In this paper, ZnO thin film is deposited on Pt/TiO₂/SiO₂/Si substrate using the sol-gel method and the effect of annealing temperature on the structural morphology and optical properties of ZnO thin films is investigated. The ZnO thin films are crystallized by the heat treatment at over 400°C. The ZnO thin film annealed at 600°C exhibits the greatest c-axis orientation and the Full-Width-Half-Maximum (FWHM) of X-ray peak is 0.4360°. A dense ZnO thin film is deposited by the growth of uniform grains with the increase of annealing temperature but when the annealing temperature increases to 700°C, the surface morphology of ZnO thin film becomes worse by the aggregation of ZnO particles. In the results of surface morphology of ZnO thin film using atomic force microscope (AFM), the surface roughness of ZnO thin film annealed at 600°C is smallest, that is, approximately 1.048 nm. For the PL characteristics of ZnO thin film, it is observed that ZnO thin film annealed at 600°C exhibits the greatest UV (ultraviolet) exciton emission at approximately 378 nm, and the smallest visible emission at approximately 510 nm among ZnO thin films annealed at various temperatures. It is deduced that ZnO thin film annealed at 600°C is formed most stoichiometrically, since the visible emission at approximately 510 nm comes from either oxygen vacancies or impurities.     

Effects of annealing temperature on the structure and photoluminescence properties of ZnO films

Zinc oxide (ZnO) films with c-orientation were deposited on Si (1 1 1) substrates at room temperature (RT) by RF-magnetron sputtering. Violet (394 and 412 nm) and green (560 and 588 nm) photoluminescence (PL) were observed from the as-deposited and annealed samples. The PL intensity was increasing with increasing annealing temperature (T_a). The 412 nm violet peak shifted from 412 to 407 nm and the 394 nm violet peak shifted from 394 to 399 nm on increasing the temperature from 500 to 900 °C, whereas no shift in PL green peaks was observed over the whole range of temperature examined. The 412 nm violet luminescence is ascribed to radiative defects related to the interface traps existing at grain boundaries. With the increase of T_a, the stress in the films changed from compressive to tensile, which is believed to have resulted in the observed 412 nm violet emission peak shifts from 412-407 nm. The 394 nm violet luminescence observed is attributed to free excitonic emission, and the increase of the crystal size may result in the 394 nm violet emission peak shifts from 394 to 399 nm. The other two PL bands located at 560 and 588 nm are attributed to oxygen deficiency.     

磁过滤阴极弧制备四面体非晶碳膜热稳定性研究

为研究磁过滤阴极弧制备的四面体非晶碳(tetrahedral amorphous carbon, ta-C)膜在自然环境中使用的热稳定性, 将ta-C膜在空气中退火3h, 退火温度分别为200、400和500℃. 用XPS和Raman谱对膜的微观结构进行表征. 结果表明, 在400及400℃以下退火, XPS谱C1_s峰和Raman谱都没有明显变化. 当退火温度为500℃时, C1_s峰峰形仍然没有变化; Raman峰I_D/I _G增大, G峰峰位未变, 峰的对称性变好. 分析显示膜中石墨颗粒长大, 但没有发生石墨化. 说明磁过滤阴极弧制备的ta-C膜因不含氢和结构致密而表现出良好的热稳定性. 另外, 在退火温度为500℃时, 样品边缘已经氧化挥发.