C离子注入对SiO2薄膜光致发光特性的影响

先用湿氧化法在单晶硅表面生长了非晶态SiO2薄膜,再用不同能量的C离子对薄膜进行注入,然后用荧光光谱分析了注入参数(注入能量、剂量)与发光特性改变的关联。研究发现,C离子注入能显著影响薄膜的发光特性,并且薄膜发光特性的改变强烈依赖于C离子的注入能量和注入剂量。对C离子注入SiO2薄膜引起发光特性改变的可能机理进行了简单讨论。     

Ge-SiO2薄膜的结构及其发光特性的研究

采用射频磁控溅射技术制备了Ge-SiO2薄膜，在N2气氛下进行了不同温度的退火处理，分析了样品在室温下的光致发光（PL）特性，为探讨其发光机制，对薄膜的结构进行了表征，XRD、XPS、FTIR谱分析说明样品的发光特性与其结构相对应，394nmPL由GeO缺陷引起，580nmPL与Ge纳米晶粒和基质SiO2界面处的发光光中心相联系。     

Optical properties of nano-silicon

We investigated the optical properties of silicon clusters and Si nanocrystallites using photolumine-scence (PL) and Raman scattering technique. Broad luminescence band in the red region was observed from Si-doped SiO₂ thin films deposited by co-sputtering of Si and SiO₂ onp-type Si (100) substrates, annealed in Ar and O₂ atmosphere. Nanocrystalline Si particles fabricated by pulsed plasma processing technique showed infrared luminescence from as grown film at room temperature. Raman spectra from these films consisted of broad band superimposed on a sharp line near 516 cm⁻¹ whose intensity, frequency, and width depend on the particle sizes arising from the phonon confinement in the nanocrystalline silicon. We also performed PL, Raman and resonantly excited PL measurements on porous silicon film to compare the optical properties of Si nanostructures grown by different techniques. An extensive computer simulation using empirical pseudo-potential method was carried out for 5–18 atoms Si clusters and the calculated gap energies were close to our PL data. Paper presented at the 5th IUMRS ICA98, October 1998, Bangalore.     

Ge/SiO2和Ge/ZnO/SiO2薄膜的磁控溅射制备及电学性能

采用射频磁控溅射方法以石英玻璃为衬底分别沉积制备出了Ge/SiO2和Ge/ZnO/SiO2薄膜。X射线衍射表明薄膜展示了明显的ZnO衍射峰和较弱的Ge衍射峰;傅里叶变换红外光谱曲线证明薄膜均具有各自的特征吸收峰;扫描电镜结果显示薄膜为颗粒状团簇结构,并且加入ZnO中间层可以有效的改善Ge层的质量。同时,对所得薄膜材料的电流-电压性能进行了研究,结果发现,Ge/SiO2薄膜的I-V曲线拟合后为斜线,相当于电阻;ZnO/SiO2薄膜为直线,可以认为是绝缘体;Ge/ZnO/SiO2薄膜在-10～10V之间电流电压呈线性关系,其电阻比Ge/SiO2薄膜小,当电压值超过15V之后,电流急剧增加而迅速使薄膜击穿,薄膜导通。     

Dependence of photoluminescence and electrical properties with rapid thermal annealing in nitrogen-implanted ZnO films

Undoped (as-grown) ZnO films grown by pulsed laser deposition on Al₂O₃ (0001) substrates were doped with nitrogen by means of an ion implantation process. Post-implantation annealing behavior in the temperature range between 500 and 700 °C has been studied by photoluminescence and Hall effect measurements. The implanted films show no peak other than the excitonic recombination emission in the as-implanted state, however, after rapid thermal annealing at 700 °C they reveal a nitrogen acceptor related emission at 3.273 eV. The as-implanted ZnO films show more electron concentrations than the as-grown, unimplanted ZnO film. In contrast, after annealing, the electron concentration in the implanted films is significantly reduced, indicating that the incorporated nitrogen becomes activated after the thermal annealing, then produces holes and eventually compensates for certain amount of electrons. The results imply that a proper nitrogen implantation and subsequent annealing may be a way to produce p-type ZnO films.     

Optical properties of SiO2-TiO2 sol-gel thin films

The optical properties of thin SiO₂-TiO₂ sol-gel composite films were investigated using exact optical models and the Forouhi-Bloomer model, (Phys. Rev. B34, 7018 (1986)), which describes the optical dispersion of amorphous dielectrics. Films deposited on glass and silicon substrates, were characterized by optical transmission and reflection measurements. Theoretical spectra have been generated and fitted to the experimental ones via standard regression analysis techniques. The (five) adjustable Forouhi-Bloomer parameters describing the dispersion of the complex refractive index, as well as the film thickness were determined. The refractive index and absorption coefficient of the films were found to depend on the molar contents of the component oxides.     

Two-dimensional modelling of diffusion of low-energy implanted arsenic in silicon at rapid thermal annealing

The two-dimensional model of arsenic diffusion in silicon at rapid thermal annealing is presented. A method of solving the nonlinear differential equations system is specified. Model calculations were performed for 15 keV As⁺ implanted in Si and annealed for 10 min at 950 °C. The results are in reasonable agreement with the experimental data, including the presence of local maximum of arsenic atoms near the surface.     

Shift in room-temperature photoluminescence of low-fluence Si+-implanted SiO2 films subjected to rapid thermal annealing

Abstract

We experimentally demonstrate the effect of the rapid thermal annealing (RTA) in nitrogen flow on photoluminescence (PL) of SiO₂ films implanted by different doses of Si⁺ ions. Room-temperature PL from 400-nm-thick SiO₂ films implanted to a dose of 3×10¹⁶ cm^?2 shifted from 2.1 to 1.7 eV upon increasing RTA temperature (950–1150 °C) and duration (5–20 s). The reported approach of implanting silicon into SiO₂ films followed by RTA may be effective for tuning Si-based photonic devices.     

退火温度对Ge/SiO2多层膜的结构和光学性能的影响

采用磁控溅射技术在石英衬底上制备出(Ge/SiO2)15多层膜,并在不同温度下对其进行退火处理。XRD和Raman结果表明:溅射态的薄膜为非晶态,当退火温度为500℃时开始出现明显的结晶衍射峰,随后晶化率明显增大,当600℃后,薄膜的晶化率几乎不变。FESEM和小角度X射线衍射结果表明:溅射态薄膜的层与层之间存在明显的界面,具有良好的周期性,升高退火温度,晶粒尺寸增大,但仍保持周期性结构。薄膜的紫外-可见光吸收光谱表明:随着退火温度的升高,吸收边发生红移,光学带隙从溅射态的1.86eV减小到600℃时的1.59eV。     

Optical and physical properties of solgel-derived GeO2:SiO2 films in photonic applications

The functionality of optical components relies heavily on the composition-dependent properties of germanosilicate materials, which include the refractive index, photosensitivity, and microstructural properties. Recent studies and parallel developments are presented of germanosilicate films with composition x of Ge content (i.e., xGeO(2):(1-x)SiO(2)) that were synthesized by the solgel process for various integrated photonic applications undertaken. The following novel aspects are discussed with respect to the effect of composition of the glassy films (0.05相似文献   

Opto-electronic properties of sputter-deposited Cu2O films treated with rapid thermal annealing

Cu₂O thin films were first deposited using magnetron sputtering at 200 °C. The samples produced were then annealed by a rapid thermal annealing (RTA) system at 550 °C in a protective atmosphere with or without the addition of oxygen. After annealing, various Cu₂O and CuO films were formed. These films were characterized, as a function of oxygen concentration in RTA, using UV-VIS photometer, four-point probe, and Hall measurement system. The results show that these Cu₂O thin films annealed at 550 °C with more than 1.2% oxygen added in the protective argon atmosphere would transform into the CuO phase. Apparently, the results of RTA are sensitive to the amount of oxygen added in the protective atmosphere. The resistivity of these Cu₂O thin films decreases with the increase in the oxygen amount in the annealing atmosphere, most likely due to the increase in carrier mobility. In addition, Cu₂O/ZnO (doped with AlSc) junctions were produced at 200 °C and annealed. The rectifying effect of P-N junction disappeared after annealing, probably due to the damage of p-n interface, which directly causes current leakage at the junction.     

Si和C共掺杂的SiO2薄膜的光致发光

采用双离子束溅射技术制备了Si和C共掺杂的SiO2薄膜,在N2气氛下进行了不同温度的退火处理。分析了样品在室温下的光致发光(PL)特性,在该样品中观察到分别位于410nm和470nm的两个发光峰。这两个发光峰的强度随着退火温度的变化呈现不同的变化趋势,表明两个发光峰的来源并不相同。用XRD和FTIR测试手段分析了样品的结构,认为470nm的发光来源于中性氧空位缺陷(O3≡Si～Si≡O3),而410nm的发光来源于Si1-xCx纳米晶粒与SiO2基质之间的界面缺陷。     

Control and characterization of structural and optical properties of ZnO thin films fabricated by thermal oxidation Zn metallic films

The physical properties of ZnO thin films fabricated by controlling thermal oxidation zinc metallic films process have been investigated. Comparative characterization of crystallographical, optical or spectroscopic properties of the samples was performed. The as-oxidized sample by rapid thermal process showed level of crystallinity degraded, higher optical transmittance in the visible and near-infrared region, and lower intensity of the near band edge emission compared to those prepared by conventional thermal oxidation. The overall results suggested that with in-depth understanding of the oxidation mechanism, rapid oxidation process could be employed as an approach to fabricate amorphous transparent oxide thin films from low-melting-point metals, which might have potential advantages in microelectronic and optoelectronic applications.     

Optical properties of TiO2 thin films after Ag ion implantation

Metal plasma ion implantation has being successfully developed for improving the electronic and optical properties of semiconductor materials. Prior to deposition, a TiO₂ colloidal suspension was synthesized by microwave-induced thermal hydrolysis of the titanium tetrachloride aqueous solution. The TiO₂ thin film was optimized to obtain a high-purity crystalline anatase phase by calcinations at 550 °C. The TiO₂ coating was uniform without aggregation, which provided good photo conversion efficiency. Ag ion implantation into the as-calcined TiO₂ thin films was conducted with 1 × 10¹⁵ ~ 1 × 10¹⁶ ions/cm² at 40 keV. The peak position and intensity of the photoluminescence and UV-Vis absorption spectra are quite sensitive to Ag doping. The optical characterization showed a shift in optical absorption wavelength towards infrared ray side, which was correlated with the structure variation of the Ag⁺ implanted TiO₂. Due to the strong capability of forming compounds between the energetic silver ions and TiO₂, the photoluminescence emission and UV-Vis absorption efficiencies were improved.     

SiO2/CdS光子晶体的制备及其光学性能

用化学浴沉淀法(CBD)在SiO2胶体晶体中生长了CdS半导体材料, 并用UV-VIS-NIR光谱仪和荧光光分度计测试了其光学性能.测试结果表明,在SiO2胶体晶体中随着CdS填充量的增加,光子带隙向长波段方向移动且变宽;当发射出的光与基体材料的光子带隙相匹配时,可控制半导体材料的光致发光,同时,可通过控制SiO2胶体颗粒粒经的大小来调节CdS的光致发光性能.     

离子注入制备掺Er富硅氧化硅材料光致发光

利用离子注入方法制备了掺Er富硅氧化硅材料,用XRD,TEM方法研究材料微观结构,并测量了样品的光致发光(PL),研究了发光强度随测量温度的变化。试验表明:在1173K以上退火,注入硅集聚,形成φ(2-4)nm的纳米晶硅(nc-Si),纳米晶硅外面包裹非晶硅(a-Si),注入的Er离子分布在非晶硅中。通过非晶硅与硅纳米晶相耦合,非晶硅吸收部分硅纳米晶对Er的激发能量,降低了Er的激发效率;在T>150K时,激发态Er与非晶硅间的能量背迁移降低了Er的发光效率。     

退火温度对Ge-SiO2薄膜结构的影响

用射频磁控溅射制备了Ge-SiO2薄膜，在N2的保护下对薄膜进行了不同温度的退火处理。使用傅里叶变换红外光谱分析（FTIR）技术，X射线衍射谱（XRD），X射线光电子能谱（XPS）分析样品的微结构，研究样品在退火中发生的结构，组分的变化，结果表明退火温度对薄膜的结构，尤其是薄膜中的GeO含量和GeO晶粒的大小的影响是显著的，并对其做了详尽的分析讨论。     

The electrical and optical properties of indium zinc tin oxide thin films with different Sn/Zn ratio

Indium zinc tin oxide (IZTO) thin films with two different chemical compositions, i.e. IZTO15 and IZTO25, where In content was fixed at 60 at.% and Sn content was 15 and 25 at.%, respectively, were deposited onto alkaline-free glass substrate at temperature from 37 °C to 600 °C. The deposition process was carried out in argon using an RF magnetron sputter. After deposition, the films were annealed in argon atmosphere at 450 °C for 30 min. The effect of substrate temperature and annealing treatment was investigated, and the minimum resistivity value of 3.44 × 10^− 4Ω.cm was obtained from the film deposited at 400 °C using IZTO25 target followed by rapid thermal annealing at 450 °C for 30 min. The average optical transmittance was kept fairly high over 80%. It was proven that both substrate temperature and thermal annealing were important parameters in lowering the electrical resistivity without deteriorating optical properties.     

Optical properties of electrochemically deposited ZnO thin films on colloidal crystal film of SiO2 microspheres

The optical properties of electrochemically deposited ZnO thin films on colloidal crystal film of SiO2 microspheres structures were studied. Colloidal crystal film of SiO2 microspheres were self-assembled by evaporation using SiO2 in solution at a constant 0.1 wt%. ZnO in thin films was then electrochemically deposited on to colloidal crystal film of SiO2 microspheres. During electrochemical deposition, the content of Zn(NO3)2 x 6H2O in solution was 5 wt%, and the process's conditions were varied between of 2-4 V and 30-120 s at room temperature, with subsequent heat-treatment between 200 and 400 degrees C. A smooth surface and uniform thickness of 1.8 microm were obtained at 3 V for 90 s. The highest PL peak intensity was obtained in the ZnO thin film heat-treated at 400 degrees C. The double layered ZnO/SiO2 colloidal crystals showed clearly better emission properties than the SiO2/ZnO and ZnO structures.