Nanocrystalline p-type-cuprous oxide thin films by room temperature chemical bath deposition method

Nanocrystalline cuprous oxide (Cu₂O) thin films were synthesized on amorphous glass substrate by using simple room temperature chemical route namely, chemical bath deposition (CBD) method. The deposition kinetics played important role to get good quality nanocrystalline films with uniform thickness. The structural, surface morphological, optical and electrical properties of the films were investigated. Crystallization and growth processes obtained micro-spherical shaped grains of Cu₂O due to agglomeration of smaller nanoparticles. An optical and electrical characterization was performed to study the optical band gap and type of electrical conductivity of the film.     

催化剂水对掺杂氟的氧化锡膜性能与结构的影响

采用常压化学气相沉积法(APCVD),以有机金属化合物-单丁三氯化锡(C4H9SnCl3,MBTC)和三氟乙烯(CF3COOH,TFA)为前驱物和掺杂剂,以水为催化剂,在线制备了F掺杂的SnO2膜;采用XRD、SEM、椭偏仪等方法研究催化剂H2O的用量对薄膜的结构和光电性能的影响.结果表明,H2O可促进反应混合气体在基板表面的热分解反应,加速薄膜沉积速率,提高薄膜结晶性能.     

Zinc tin oxide thin films prepared by MOCVD with different Sn/Zn ratios

Zinc tin oxide(ZTO) thin films, with zinc acetate and tributyltin chloride as raw materials, were deposited on glass substrates by the method of metal organic chemical vapor deposition(MOCVD). The crystallization, microstructure and optical properties were investigated by scanning electronic microscope(SEM),X-ray diffraction(XRD) and ultraviolet-visible(UV-Vis)spectrophotometer. The results show that with the increase in Sn/Zn ratio, the crystal changes from wurtzite to rutile phase. When the ratio reaches 11:18,the intensity of Zn_2SnO_4 peaks appears to be the strongest and the optical band gap is about 3.27 eV. Calculated by the envelope method, the thickness of the ZTO thin films is 713.24 nm.Measured by UV-Vis spectrophotometer, the transmittance of the ZTO thin films reaches up to 80% in the wavelength range of 400-1000 nm when the Sn/Zn ratio is 7:18.     

HWCVD与RF-PECVD复合技术制备微晶硅薄膜的性能*

采用热丝化学气相沉积(HWCVD)和射频等离子体化学气相沉积(RF-PECVD)相结合的技术,在普通载玻片和聚酰亚胺衬底上沉积制备微晶硅薄膜。系统考查了热丝到衬底的距离对沉积薄膜结构和性能的影响规律,用拉曼光谱仪、X-射线衍射仪(XRD)、紫外可见光纤光谱仪对薄膜的晶化率、微观结构和光学性能进行研究。结果表明:薄膜沉积速率最高可达到0.73nm/s,晶化率和禁带宽度分别可以在0%～78%和0.86～1.28eV变化,射频等离子体的引入有助于多晶硅薄膜的(220)择优生长,HWCVD的引入有助于薄膜晶化。     

Studies of nanostructured copper/hydrogenated amorphous carbon multilayer films

Nanostructured copper/hydrogenated amorphous carbon (a-C:H) multilayer grown in a low base vacuum (1 × 10⁻³ Torr) system combining plasma-enhanced chemical vapor deposition and sputtering techniques. These nanostructured multilayer were found to exhibit improved electrical, optical, surface and structural properties, compared to that of monolayer a-C:H films. The residual stresses of such multilayer structure were found well below 1 GPa. Scanning electron microscopy and atomic force microscopy results revealed a nanostructured surface morphology and low surface roughnesses values. X-ray photoelectron spectroscopy, secondary ion mass spectroscopy and energy dispersive X-ray analysis confirmed a very small amount of copper in these films. These structures exhibited very high optical transparency in the near infrared region (∼90%) and the optical band gap varied from 1.35 to 1.7 eV. It was noticed that the temperature dependent conductivity improved due to the presence of both copper and the nano-structured morphology.     

Structural,optical properties and optical modelling of hydrothermal chemical growth derived ZnO nanowires

ZnO nanowire films were produced at 90 °C using a hydrothermal chemical deposition method, and were characterised with scanning electron microscopy, optical transmission spectrometry and X-ray diffraction. The results showed that the optical band gap is 3.274–3.347 eV. Film porosity and microstructure can be controlled by adjusting the pH of the growth solution. ZnO nanowire films comprise a 2-layer structure as demonstrated by SEM analysis, showing different porosities for each layer. XRD analysis shows preferential growth in the (002) orientation. A comprehensive optical modelling method for nanostructured ZnO thin films was proposed, consisting of Bruggeman effective medium approximations, rough surface light scattering and O'Leary-Johnson-Lim models. Fitted optical transmission of nanostructured ZnO films agreed well with experimental data.     

Doping and annealing effects on ZnO:Cd thin films by sol-gel method

In this article, ZnO:Cd films were successfully deposited on glass substrates by a sol-gel technique. The influence of doping concentration and annealing temperature effects was carefully investigated. All films exhibited c-axis preferential orientation and optical transparency with visible transmittance >80%. The minimum room temperature resistivity of 0.0341 Ω cm was obtained with 10 at.% Cd doping under 600 °C annealing temperature. The optical band gap of ZnO:Cd film was reduced as Cd doping concentration increased, while the band gap increased with the increase of annealing temperature.     

Synthesis and characterization of Cu2ZnSnS4 thin films grown by PLD: Solar cells

As-deposited and annealed Cu₂ZnSnS₄ (CZTS) thin films have been synthesized onto Mo coated glass substrates at different deposition times using pulsed laser deposition (PLD) technique. The effect of deposition time (film thickness) and annealing onto the structural, morphological, compositional and optical properties of CZTS thin films have been investigated. The polycrystalline CZTS thin films with tetragonal crystal structure have been observed from structural analysis. FESEM and AFM images show the smooth, uniform, homogeneous and densely packed grains and increase in the grain size after annealing. The internal quantitative analysis has been carried out by XPS study which confirms the stoichiometry of the films. The optical band gap of CZTS films grown by PLD is about 1.54 eV, which suggests that CZTS films can be useful as an absorber layer in thin film solar cells. Device performance for deposited CZTS films has been studied.     

室温下反应磁控溅射沉积氧化钛薄膜光学性能和力学性能研究

目的通过对比不同溅射功率和氧气分压下氧化钛薄膜性能的变化规律,分析其力学性能和光学性能的关系。方法在室温条件下,采用直流反应磁控溅射技术在K9玻璃基底上沉积TiO_2薄膜,通过紫外可见红外分光光度计和椭偏仪对薄膜的光学特性进行分析,通过微纳米压痕技术对薄膜的力学性能进行表征。结果在给定工艺参数范围内,薄膜的光学折射率与纳米硬度和弹性模量正相关,随着溅射靶功率的增大,所制备薄膜的折射率、纳米硬度和弹性模量随之增大,而薄膜的光学带隙则随着溅射功率的增大而下降。同时,O_2流量对薄膜的光学性能和力学性能的影响更明显,在较低O_2流量条件下(Q(Ar)/Q(O_2)=10/1),所制备薄膜的折射率减小而光学带隙变大,随着O_2流量进一步减少(Q(Ar)/Q(O2)=20/1),薄膜的折射率增大而光学带隙减小,但薄膜的纳米硬度和弹性模量随O_2流量的减少而下降。结论磁控溅射沉积TiO_2薄膜的折射率与其光学带隙反向相关,而仅在适量氧气条件下所制备的薄膜的力学性能与光学特性有相关性。     

Investigation of gas phase mechanisms during deposition of diamond films

The deposition of diamond films is investigated by optical emission spectroscopy measurements. Using the microwave chemical vapour deposition technique, the system C:H:O is surveyed starting from hydrogen-rich oxygen-free mixtures by gradually adding oxygen and reducing the hydrogen content until finally reaching C:H:O = 1:4:1, i.e. CH₄ + O₂. CH and C₂ are shown to give good measures for different active carbon species, CH being correlated with the growth rate while C₂ correlates inversely to the film quality. The main role of O₂ is the transformation of active carbon into the more stable carbon monoxide.     

Properties of multilayer gallium and aluminum doped ZnO(GZO/AZO) transparent thin films deposited by pulsed laser deposition process

Multilayer gallium and aluminum doped ZnO (GZO/AZO) films were fabricated by alternative deposition of Ga-doped zinc oxide(GZO) and Al-doped zinc oxide(AZO) thin film by using pulsed laser deposition(PLD) process. The electrical and optical properties of these GZO/AZO thin films were investigated and compared with those of GZO and AZO thin films. The GZO/AZO (1:1) thin film deposited at 400 °C shows the electrical resistivity of 4.18×10^?4 ωcm, an electron concentration of 7.5×10²⁰/cm³, and carrier mobility of 25.4 cm²/(V·s). The optical transmittances of GZO/AZO thin films are over 85%. The optical band gap energy of GZO/AZO thin films linearly decreases with increasing the Al ratio.     

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.     

Characterization of CuInS2 thin films prepared by sulfurization of Cu-In precursor

CuInS2 thin films were prepared by sulfurization of Cu-In precursors. The influences of the deposition sequence of Cu and In layers, such as Cu/In, Cu/In/In, and In/Cu/In, on structure, topography, and optical properties of CuInS2 thin films were investigated. X-ray diffraction results show that the deposition sequence of Cu and In layers affects the crystalline quality of CuInS2 films. Atomic force microstructure images reveal that the grain size and surface roughness are related to the deposition sequence used. When the deposition sequence of precursor is In/Cu/In, the CuInS2 thin films show a single-phase chalcopyrite structure with （112） preferred orientation. The surface morphology of CIS films is uniform and compacted. The absorption coefficient is larger than 10^4 cm^-1 with optical band gap Egclose to 1.4 eV.     

Boron and fluorine doped ZnO films obtained from zinc chloride precursor via chemical spray pyrolysis

Both boron (1, 2 and 3 at %) and fluorine (1, 3, 5 and 7 at %) doped zinc oxide thin films (ZnO:B:F) were fabricated using zinc chloride precursor by airbrush spray pyrolysis technique on glass substrates. X-ray diffraction (XRD) measurements show that all ZnO:B:F films have hexagonal wurtzite structure with a preferential growth along the [0 0 2] direction on glass substrates. Scanning electron microscope (SEM) results show that the morphologies of all doped films have a regular hexagonal shape. The optical measurements reveal that ZnO:B:F films have a direct band gap and optical energy gaps are increasing with boron and fluorine concentration. The optical transmittance of B and F doped ZnO films is measured very low due to columnar structure of prepared films. Moreover, it has been observed that the doping of ZnO films with boron and fluorine decreases the electrical resistance, and the lowest resistances of films were observed at 1%B–3%F and 2%B–3%F concentrations.     

掺硼和掺磷的氢化纳米硅薄膜及其应用于类叠层太阳电池的研究

采用射频等离子体增强化学气相沉积法,制备了掺硼和掺磷的氢化纳米硅薄膜(nc-Si∶H),并将其应用于纳米硅薄膜类叠层太阳电池中。分析了薄膜样品的光学性能及表面形貌,结果表明:P型掺硼纳米硅薄膜的光学带隙为2.189 eV,电导率为8.01 S/cm,霍尔迁移率为0.521 cm2/(V.S),载流子浓度为9.61×1019/cm3;N型掺磷纳米硅薄膜的光学带隙为1.994 eV,电导率为1.93 S/cm,霍尔迁移率为1.694 cm2/(V.S),载流子浓度为7.113×1018/cm3;两者的晶粒尺寸都在3～5 nm之间,晶态比都在35%～45%之间,并且颗粒沉积紧密,大小比较均匀。制备了大小为20 mm×20 mm,结构为Al/AZO/p-nc-Si∶H/i-nc-Si∶H/n-nc-Si∶H/p-nc-Si∶H/i-nc-Si∶H/n-c-Si/Al背电极的纳米硅薄膜类叠层太阳电池,通过I-V曲线测试,其VOC达到544.3 mV,ISC达到85.6 mA,填充因子为65.7%。     

Microstructure and tribological properties of the a-C:H films deposited by magnetron sputtering with CH4/Ar mixture

Hydrogenated amorphous carbon (a-C:H) films were deposited on steel and silicon wafers by unbalanced magnetron sputtering under different CH₄/Ar ratios. Microstructure and properties of the a-C:H films were investigated via Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, Atomic force microscopy (AFM) and substrate curvature method. The results revealed that CH₄/Ar ratio played an important role in the H content but acted a little function on the sp³/sp² ratio of the films. Also, the internal stress of those films was relatively low (< 1 GPa), and the deposition rate decreased firstly and then increased with the decrease of the CH₄ fraction. The film deposited under CH₄/Ar = 1/1 (55 sccm/55 sccm) with moderate sp³ C-H / sp³ C-C had the best tribological properties. The composition, microstructure and properties of the a-C:H films were strongly dependent on the deposition process and composition of reactant gases.     

TiSiO非晶结构光学薄膜的性能调控机理研究进展

TiSiO复合薄膜的制备方法主要包括溶胶-凝胶、物理气相沉积和化学气相沉积等,针对不同制备工艺条件下SiO2改性TiO2的微观结构与光学参量的调控机理的研究,仍处于探索阶段。综述了近年来国内外在不同工艺条件下沉积的TiSiO薄膜的结构和光学性质,从溶胶体系和热处理工艺两方面,对溶胶-凝胶工艺制备的TiSiO薄膜展开论述,分别归纳了溶胶体系和热处理工艺调控TiSiO薄膜的结构和光学性质的一般规律;从溅射工艺和蒸发工艺两方面对物理气相沉积工艺制备的TiSiO薄膜展开论述,分别阐述了在溅射工艺和蒸发工艺过程中,调控TiSiO薄膜的结构和光学性质的一般规律;从低（常）压化学气相沉积和等离子增强化学气相沉积等方面,对化学气相沉积工艺制备的TiSiO薄膜展开论述,分别阐述了在不同化学气相沉积技术中,通过调节一些重要参数调控薄膜结构和性能的一般规律。总结了不同工艺制备并调控TiSiO薄膜的一般规律的内在联系,并指出了这类薄膜制备工艺存在的问题和后续的研究方向。     

Thermoeffusion of hydrogen in a-C : H films prepared by glow discharge

The structure and properties of hydrogen-doped amorphous carbon (a-C : H) films are determined by the hydrogen content and the structure of the hydrogen bonding with the lattice.

Study of the thermal effusion of hydrogen (TEH) provides information concerning both the thermal stability of the films and the chemical bonding of hydrogen.

Wild and Koidl [1] measured the TEH in a-C : H films as a function of the bias potential V_b. They found that as V_b was increased from 50 to 500 V, the TEH threshold temperature increased from 300 to 600 °C. In a study of the thermal stability of a-C : H films prepared by glow discharge, Watanabe and Okumura [2] observed that on heating to 350 °C the thickness and optical gap of the films decreased and at still higher temperatures the films decomposed. Nadler et al. [3] investigated the thermal annealing effect in films prepared by the decomposition of hydrocarbons. On annealing at 500 °C, they observed hydrogen effusion from sp³ states and formation of C=C bonds, accompanied by a decreased transparency of the films.

In an investigation of a-C : H films prepared by r.f. glow discharge, we observed changes in the structure of the amorphous network and of the hydrogen bonding with the lattice as well as in the electronic properties of such films [4]. The data obtained suggest that TEH occurs differently in a-C : H films of different structures. Therefore it would be of interest to experiment on the TEH in a-C : H films.     

Rutile-type titanium oxide films synthesized by filtered arc deposition

A filtered arc-deposition system was used to synthesize titanium oxide films by evaporating titanium ions in an oxygen environment. Fourier transform infrared spectroscopy and X-ray diffraction analysis show that the films exhibit the rutile-type structure. X-ray photoelectron spectroscopy reveals that a small amount of Ti²⁺ and Ti³⁺ still exists although Ti⁴⁺ is the main component in the films. The preferred orientation of the films is dependent on the substrate bias and oxygen pressure. Titanium oxide films with (101) and (002) preferred orientation were prepared by changing substrate bias and oxygen pressure. Ultraviolet–visible absorption spectroscopy was used to determine the optical band gap of the prepared films. The results show that the band gap of the films prepared under zero substrate bias is 2.39 eV. When the substrate bias is larger than −100 V, the optical band gap of the films is about 3.33 eV.     

Effect of annealing on pulsed laser deposited zirconium oxide thin films

Zirconium oxide thin films were deposited using pulsed laser ablation from a ceramic ZrO₂ target on unheated substrates. Subsequently, the films were annealed in air in the temperature range 400-800 °C. The films were characterized by X-ray diffraction, atomic force microscopy, X-ray photoelectron spectroscopy, and optical spectroscopy to investigate the variation of the structural, chemical, and optical properties upon annealing. As-deposited films were amorphous and had a large surface density of ablated particles. Annealing resulted in the growth of monoclinic nano-crystalline, uniform, and transparent films that were slightly sub-stoichiometric. The annealed films were compact and had high values of the refractive index. Extinction coefficients were small, and may be related to the presence of defects. The films exhibited the presence of an indirect band gap, related to defects, and a direct band gap, related to fundamental absorption.