氧流量对磁控溅射ZrO2薄膜光学性能的影响

采用反应磁控溅射法在k9玻璃基底上沉积ZrO2薄膜.用轮廓仪、椭圆偏振仪和分光光度计,分别测试薄膜的厚度、折射率、消光系数和透过率,研究了不同氧流量对薄膜沉积速率和光学特性的影响.结果表明:随着氧气流量增加到22～24 mL/min(标准状态下)时,沉积速率从6.8 nm/s下降到2.5 nm/s,并趋于稳定;在入射波...     

Study of bactericidal efficiency of magnetron sputtered TiO2 films deposited at varying oxygen partial pressure

TiO₂ thin films have been deposited at different Ar:O₂ gas ratios (20:80,70:30,50:50,and 40:60 in sccm) by rf reactive magnetron sputtering at a constant power of 200 W. The formation of TiO₂ was confirmed by X-ray photoelectron spectroscopy (XPS). The oxygen percentage in the films was found to increase with an increase in oxygen partial pressure during deposition. The oxygen content in the film was estimated from XPS measurement. Band gap of the films was calculated from the UV-Visible transmittance spectra. Increase in oxygen content in the films showed substantial increase in optical band gap from 2.8 eV to 3.78 eV. The Ar:O₂ gas ratio was found to affect the particle size of the films determined by a transmission electron microscope (TEM). The particle size was found to be varying between 10 and 25 nm. The bactericidal efficiency of the deposited films was investigated using Escherichia coli (E. coli) cells under 1 h UV irradiation. The growth of E. coli cells was estimated through the Optical Density measurement by UV-Visible absorbance spectra. The qualitative analysis of the bactericidal efficiency of the deposited films after UV irradiation was observed through SEM. A correlation between the optical band gap, particle size and bactericidal efficiency of the TiO₂ films at different argon:oxygen gas ratio has been studied.     

直流磁控溅射法在玻璃基片上制备TiN薄膜

采用直流反应磁控溅射法在玻璃片上制备了TiN薄膜,研究不同制备工艺条件与薄膜性能之间的关系。用紫外-可见光分光光度计测试了不同沉积时间和N2流量条件下TiN薄膜透光率;用X射线衍射仪分析了不同N2流量和溅射功率条件下TiN薄膜结构;用扫描电镜(SEM)观察了TiN薄膜的表面腐蚀形貌,用恒电位仪对TiN薄膜的耐腐蚀性进行了分析。结果表明:当沉积时间为2min,N2流量为15mL/min时,在可见光区有较高的透光率,在近红外区的透光率很低;当N2流量为15mL/min,溅射功率为4kW时,TiN薄膜的结晶最致密;当溅射功率为4kW时,TiN薄膜具有较好的耐腐蚀性。     

Influence of O2/Ar flow ratio on the structure and optical properties of sputtered hafnium dioxide thin films

Hafnium dioxide (HfO₂) thin films were deposited on a quartz substrate by RF reactive magnetron sputtering. The influence of O₂/Ar flow ratio on the deposition rate, structure and optical properties of HfO₂ thin films were systematically studied using X-ray diffraction (XRD), scan electron microscopy (SEM) and UV-visible spectroscopy. The results show that the deposition rate decreases obviously when the O₂/Ar flow ratio increases from 0 to 0.25 and then, decreases little as the O₂/Ar flow ratio further increases to 0.50. The HfO₂ thin films prepared are all polycrystalline with a monoclinic phase. The thin film deposited with pure argon shows a preferential growth and has considerably improved crystallinity and much larger crystallite size. Meanwhile, after oxygen is introduced into the deposition, the thin films prepared have random orientation, weakened crystallinity and smaller crystallite size. The refractive index is higher for the thin film deposited without oxygen and increases as the O₂/Ar flow ratio increases from 0.25 to 0.50. The band gap energy of the thin film increases with an increasing O₂/Ar flow ratio.     

Effect of annealing and O2 pressure on structural and optical properties of pulsed laser deposited TiO2 thin films

In this paper, effect of annealing and O₂ pressure on the structural and optical properties of pulsed laser deposited thin films of TiO₂ is reported. XRD, FTIR spectra and SEM images confirm that at high annealing temperatures, the rutile phase and crystalline quality of thin films increases. Higher pressure of O₂ during deposition improves the rutile phase and favors the rod like growth of TiO₂ thin film. The red shift in photoluminescence (PL) spectra of TiO₂ thin films with annealing temperature is reported. Contact angle measurement data for the thin films reveals the hydrophobic nature of the films. The very low reflectivity (～10%) reported in this paper may be promising for anti-reflection coating applications of pulsed laser deposited TiO₂ thin films.     

Effect of annealing temperature on the structure and optical properties of sputtered TiO2 films

TiO₂ thin films were deposited by DC reactive magnetron sputtering. Some TiO₂ thin films samples were annealed for 5 min at different temperatures from 300 to 900 °C. The structure and optical properties of the films were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (SEM) and ultraviolet-visible (UV-vis) spectrophotometry, respectively. The influence of the annealing temperature on the structure and optical properties of the films was investigated. The results show that the as-deposited TiO₂ thin films are mixtures of anatase and rutile phases, and possess the column-like crystallite texture. With the annealing temperature increasing, the refractive index and extinction coefficient increase. When the annealing temperature is lower than 900 °C, the anatase phase is the dominant crystalline phase; the weight fraction of the rutile phase does not increase significantly during annealing process. As the annealing temperature rises to 900 °C, the rutile phase with the large extinction coefficient becomes the dominant crystalline phase, and the columnar structure disappears. The films annealed at 300 °C have the best optical properties for the antireflection coatings, whose refractive index and extinction coefficient are 2.42 and 8 × 10⁻⁴ (at 550 nm), respectively.     

Effect of annealing temperature on optical band-gap of amorphous indium zinc oxide film

The effect of annealing temperature on the electrical and optical properties of indium zinc oxide (IZO) (In₂O₃:ZnO = 90:10 wt.%) thin films has been investigated. The IZO thin films were deposited on glass substrates by radio frequency magnetron sputtering and then subjected to annealing in a mixed ambient of air and oxygen at 100, 200 and 300 °C. All the IZO films were found to have amorphous structure. With the increase of the annealing temperature, the carrier concentration decreased and the resistivity increased. The average transmittance of IZO thin films decreased slightly with annealing temperature. Interestingly, a systematic reduction of the optical band-gap from 3.79 eV to 3.67 eV was observed with annealing temperature. The change in optical band-gap was observed to be caused predominantly by Burstein-Moss band-gap widening effect suggesting unusual absence of band narrowing effect. The effects on optical and electrical properties of IZO films have been discussed in detail.     

Influence of heat treatment on the particle size of nanobrookite TiO2 thin films produced by sol-gel method

Pure nanobrookite titania (TiO₂) thin films were deposited on glass substrates by the spin-coating method using titanium butoxide and acetic acid. The particle sizes of TiO₂ films were controlled by heat treatment temperatures. The activation energy for particle growth was calculated as 23.1 kJ/mol. The structural and optical properties of the nanobrookite TiO₂ thin films were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), ultraviolet-visible absorption spectroscopy (UV-vis), and Fourier transform infrared spectroscopy (FTIR).     

Metallic sputtering growth of high quality anatase phase TiO2 films by inductively coupled plasma assisted DC reactive magnetron sputtering

Anatase phase titanium dioxide (TiO₂) films were deposited on unheated glass substrate by using inductively coupled plasma (ICP) assisted direct current (DC) reactive magnetron sputtering. Oxygen and argon were introduced into the chamber in the vicinity of the substrate and the target, respectively. In order to obtain high deposition rate, all depositions were carried out in the metallic mode of sputtering. X-ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscopy were used for the characterization of film structure and UV-VIS spectrophotometer was employed for the analysis of film optical properties. The TiO₂ film grown at an rf power of 500 W and an oxygen partial pressure of 0.20 Pa consists of an essentially complete anatase phase nanocrystallites. This anatase phase TiO₂ film exhibits a high transmittance of 85% in the visible region. The lattice spacing of 0.352 nm and the optical band gap of 3.22 eV of this anatase phase TiO₂ film match with the standard values of the bulk anatase well. Anatase phase TiO₂ films of high quality, in terms of both a high degree of crystallinity and a good oxygen stoichiometry, have been produced in the metallic mode of sputtering at temperature lower than 200 °C.     

Fabrication of patterned TiO2 thin film by a wet process

Hydrophobic/hydrophilic patterned TiO₂ thin film was successfully fabricated on a glass substrate by a wet process. A micro-nano complex structure with a high roughness was fabricated by a layer-by-layer selfassembly and liquid phase deposition (LPD) method. To fabricate superhydrophobic TiO₂ thin films, TiO₂ nanoparticles were deposited on the surface of (PAH/PAA) thin film by a LPD method and the surface of TiO₂ was modified by a hydrophobic treatment using fluoroalkyltrimethoxysilane. The RMS roughness and water contact angle of the prepared TiO₂ thin film were ca. 65.6 nm and ca. 155°. The superhydrophobic surface exposed to UV light changed to a hydrophilic surface by the photocatalytic property of TiO₂ to decompose a hydrophobic group. Finally, hydrophobic/hydrophilic patterned TiO₂ thin film with a 300 ??m dot size was fabricated. The surface morphology, transmittance, surface roughness and water contact angle of the prepared thin films were measured by a field emission scanning electron microscope, an atomic force microscope, a UV-Vis spectrophotometer and a contact angle meter.     

Controlling the particle size of nanobrookite TiO2 thin films

In this study, pure nanobrookite TiO₂ thin films were successfully deposited on glass substrates with the spin-coating method using titanium butoxide and acetic acid. The particle size of TiO₂ films was controlled by the water:AcAc volume ratio. This study shows that it is possible to obtain single oriented pure brookite films. The structural and optical properties of the nanobrookite TiO₂ thin films were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), ultraviolet-visible spectroscopy (UV-vis), scanning electron microscopy (SEM), spectrophotometer (NKD), and Fourier transform infrared spectrometer (FTIR).     

Reactive sputtering of TiOxNy coatings by the reactive gas pulsing process: Part II: The role of the duty cycle

The reactive gas pulsing process (RGPP) was used to deposit titanium oxynitride thin films by dc reactive magnetron sputtering. A titanium target was sputtered in a reactive atmosphere composed of Ar + O₂ + N₂. Argon and nitrogen gases were continuously introduced into the sputtering chamber whereas oxygen was injected with a well-controlled pulsing flow rate following a rectangular and periodic signal. A constant pulsing period T = 45 s was used for every deposition and the duty cycle α = t_ON/T was systematically changed from 0 to 100%. The operating conditions were investigated taking into account the poisoning phenomena of the target surface by oxygen and nitrogen. Kinetics of poisoning were followed from measurements of the total sputtering pressure and titanium target potential during the depositions. Deposition rate and optical transmittance of titanium oxynitride coatings were also analysed and correlated with the process parameters. Pulsing the oxygen flow rate with rectangular patterns and using suitable duty cycles, RGPP method allows working according to reversible nitrided-oxidised target conditions and leads to the deposition of a wide range of TiO_xN_y thin films, from metallic TiN to insulating TiO₂ compounds.     

Structural and dielectric properties of Bi2Zn2/3Nb4/3O7 thin films prepared by pulsed laser deposition at low temperature for embedded capacitor applications

Bi₂Zn_2/3Nb_4/3O₇ thin films were deposited on Pt/TiO₂/SiO₂/Si(1 0 0) substrates at a room temperature under the oxygen pressure of 1-10 Pa by pulsed laser deposition. Bi₂Zn_2/3Nb_4/3O₇ thin films were then post-annealed below 200 °C in a rapid thermal process furnace in air for 20 min. The dielectric and leakage current properties of Bi₂Zn_2/3Nb_4/3O₇ thin films are strongly influenced by the oxygen pressure during deposition and the post-annealing temperature. Bi₂Zn_2/3Nb_4/3O₇ thin films deposited under 1 Pa oxygen pressure and then post-annealed at a temperature of 150 °C show uniform surface morphologies. Dielectric constant and loss tangent are 57 and 0.005 at 10 kHz, respectively. The high resolution TEM image and the electron diffraction pattern show that nano crystallites exist in the amorphous thin film, which may be the origin of high dielectric constant in the Bi₂Zn_2/3Nb_4/3O₇ thin films deposited at low temperatures. Moreover, Bi₂Zn_2/3Nb_4/3O₇ thin film exhibits the excellent leakage current characteristics with a high breakdown strength and the leakage current density is approximately 1 × 10⁻⁷ A/cm² at an applied bias field of 300 kV/cm. Bi₂Zn_2/3Nb_4/3O₇ thin films are potential materials for embedded capacitor applications.     

氧氩流量比对溅射氧化钒薄膜结构和光学性能的影响

采用射频反应磁控溅射方法制备氧化钒(VOx)薄膜,对样品的沉积速率、物相结构、表面形貌和可见光波段的透过率进行表征,研究了在沉积气压一定的情况下,氧氩流量比对氧化钒薄膜结构和光学性能的影响。结果表明,改变氧氩流量比可明显改变薄膜结构,随着氧气比例的增加,沉积速率下降,薄膜表面出现了颗粒结构,颗粒尺寸具有增大的趋势,光透过率增大。     

Microstructures of SiO2 and TiOX films deposited by atmospheric pressure inductively coupled micro-plasma jet

Atmospheric-pressure inductively coupled micro-plasma jet was used for deposition of SiO₂ and TiO_x thin films. Si and Ti alkoxides respectively were vaporized into Ar gas to be decomposed thermally in the Ar plasma jet, being deposited as the metal oxide films. Microstructures of the films were investigated as changing the plasma conditions such as Ar gas flow rate and concentration of the alkoxides in Ar gas. The SiO₂ and TiO_x films deposited at higher Ar gas flow rates were composed of particles of micron or submicron sizes. The SiO₂ film was composed of a single layer of the particles and the particles sometimes formed unique aggregation structures. On the other hand, the TiO_x film had a structure in which the particles were piled up randomly. The structures suggested that the SiO₂ particles grew on the substrate whereas TiO_x particles were formed in plasma gas phase.     

Fabricating TiO2 Photocatalysts by rf Reactive Magnetron Sputtering at Varied Oxygen Partial Pressures

Titanium dioxide (TiO₂) thin films were fabricated onto non-alkali glass substrates by rf reactive magnetron sputtering at room temperature using Ti-metal target at varied oxygen partial pressure [O₂/(Ar + O₂)]. The sputtering deposition was performed under an rf power of 200 W. The target to substrate distance was kept at 80 mm, and the total gas pressure was 10 mTorr after 2 h of deposition. It was found that the crystalline structure, surface morphology, and photocatalytic activities of the TiO₂ thin films were affected by the oxygen partial pressure during deposition. The XRD patterns exhibited a broad-hump shape indicating the amorphous structure of TiO₂ thin films. The thin films deposited at a relatively high value of oxygen partial pressure (70%) had a good photo-induced decomposition of methylene blue (MB), photo-induced hydrophilicity, and had a small grain size.     

Annealing driven performance and optical effects in nanocrystalline SnO2 thin films induced by pulsed delivery

Tin dioxide thin films were prepared successfully by pulsed laser deposition techniques on glass substrates. The thin films were then annealed for 30 min from 50 °C to 550 °C at 50 °C intervals. The influence of the annealing temperature on the microstructure and optical properties of SnO₂ thin films was investigated using X-ray diffraction, optical transmittance and reflectance measurements. Various optical parameters, such as optical band gas energy, refractive index and optical conductivity were calculated from the optical transmittance and reflectance data recorded in the wavelength range 300-2500 nm. We found that the SnO₂ thin film annealed at temperatures up to 400 °C is a good window material for solar cell application. Our experimental results indicated that SnO₂ thin films with the high optical quality could be synthesized by pulsed laser deposition techniques.     

Influence of oxygen partial pressure on electrical and optical properties of Zn0.93Mn0.07O thin films

The Zn_1−xMn_xO (x = 0.07) thin films were grown on glass substrates by direct current reactive magnetron cosputtering. The influence of oxygen partial pressure on the structural, electrical and optical properties of the films has been studied. X-ray-diffraction measurement revealed that all the films were single phase and had wurtzite structure with c-axis orientation. The experimental results indicated that there was an optimum oxygen partial pressure where the film shows relative stronger texture, better nano-crystallite and lower surface roughness. As the oxygen partial pressure increases, the carrier concentration systematically decreases and photoluminescence peaks related to zinc interstitials gradually diminish. The minimal resistivity of 70.48 Ω cm with the highest Hall mobility of 1.36 cm² V⁻¹ s⁻¹ and the carrier density of 6.52 × 10¹⁶ cm⁻³ were obtained when oxygen partial pressure is 0.4. All films exhibit a transmittance higher than 80% in the visible region, while the deposited films showed a lower transmittance when oxygen partial pressure is 0.4. With the increasing of oxygen partial pressure, the peak of near-band-edge emission has firstly a blueshift and then redshift, which shows a similar trend to the band gap in the optical transmittance measurement.     

Effect of substrate rotation speed on structure and properties of Al-doped ZnO thin films prepared by rf-sputtering

Al-doped ZnO (AZO) thin films were deposited on glass substrates by rf-sputtering at room temperature. The effects of substrate rotation speed (ω_S) on the morphological, structural, optical and electrical properties were investigated. SEM transversal images show that the substrate rotation produces dense columnar structures which were found to be better defined under substrate rotation. AFM images show that the surface particles of the samples formed under substrate rotation are smaller and denser than those of a stationary one, leading to smaller grain sizes. XRD results show that all films have hexagonal wurtzite structure and preferred c-axis orientation with a tensile stress along the c-axis. The average optical transmittance was above 90% in UV-Vis region. The lowest resistivity value (8.5×10^?3 Ω·cm) was achieved at ω_S=0 r/min, with a carrier concentration of 1.8×10²⁰ cm^?3, and a Hall mobility of 4.19 cm²/(V·s). For all other samples, the substrate rotation induced changes in the carrier concentration and Hall mobility which resulted in the increasing of electrical resistivity. These results indicate that the morphology, structure, optical and electrical properties of the AZO thin films are strongly affected by the substrate rotation speed.     

Elaboration and characterization of nanocrystalline TiO2 thin films prepared by sol–gel dip-coating

Nanocrystalline TiO₂ thin films were deposited on a ITO coated glass substrate by sol–gel dip coating technique, the layers undergo a heat treatment at temperatures varying from 300 to 450 °C. The structural, morphological and optical characterizations of the as deposited and annealed films were carried out using X-ray diffraction (XRD), Raman spectroscopy, Atomic Force Microscopy (AFM), visible, (Fourier-Transform) infrared and ultraviolet spectroscopy, Fluorescence and spectroscopic ellipsometry. The results indicate that an anatase phase structure TiO₂ thin film with nanocrystallite size of about 15 nm can be obtained at the heat treatment temperature of 350 °C or above, that is to say, at the heat treatment temperature below 300 °C, the thin films grow in amorphous phase; while the heat treatment temperature is increased up to 400 °C or above, the thin film develops a crystalline phase corresponding to the titanium oxide anatase phase. We have accurately determined the layer thickness, refractive index and extinction coefficient of the TiO₂ thin films by the ellipsometric analysis. The optical gap decreases from 3.9 to 3.5 eV when the annealing temperature increases. Photocatalytic activity of the TiO₂ films was studied by monitoring the degradation of aqueous methylene blue under UV light irradiation and was observed that films annealed above 350 °C had good photocatalytic activity which is explained as due to the structural and morphological properties of the films.