非晶硅太阳能电池背反ZnO:Al薄膜制备

以ZnO:Al(2%Al2O3,质量分数)为靶材,用射频磁控溅射在玻璃衬底上制备ZnO:Al薄膜,分析了各沉积参数对薄膜光电性能的影响。结果表明:溅射功率对ZnO:Al的透过率影响最大,其次是反应腔室压力,而衬底温度对透过率几乎没有影响。ZnO:Al的电阻率主要取决于衬底温度和溅射功率。综合考虑透过率和电阻率,确定了背反ZnO:Al的最佳沉积参数(衬底温度为200℃,溅射功率为200W,反应腔室压力为0.6Pa),得到了透过率大于85%,电阻率最小为7.6×10-4Ωcm的ZnO:Al薄膜。制备了ZnO:Al/Ag/ss(stainless steel)背反电极,并将其用于非晶硅太阳能电池。与无背反的不锈钢衬底上的电池相比,非晶硅太阳能电池短路电流密度增加了16%。     

Effect of gas-timing technique on structure and optical properties of sputtered zinc oxide films

Zinc oxide thin films were prepared by the RF magnetron sputtering using a gas-timing technique whereby the flow of argon into the sputtering chamber was controlled by an on–off sequence. With this technique, polycrystalline ZnO thin films on glass substrates have been achieved without any thermal treatment of the substrate. In addition, the RF power and the gas-timing sequence can be fine-tuned to produce the hexagonal structure of ZnO thin films. X-ray diffraction (XRD) measurements confirm a (0 0 2) plane oriented wurtzite structure ZnO thin films. The optimized conditions for this hexagonal structure are an RF power of 30 W and an on–off gas-timing sequence of 50:2 s. The root mean square surface roughness of ZnO thin films measured by atomic force microscopy are in the range of 6.4–11.5 nm. The optical transmittance of ZnO thin films is over 85% in the visible range.     

Preparation of Fluorine-Containing Indium Tin Oxide Sputtering Targets using Spark Plasma Sintering Process

Fluorine-containing indium tin oxide (F-ITO) sputtering targets were prepared using spark-plasma-sintering (SPS) process. The initial powder, which was prepared by reacting ITO with HF, was sintered to the 10 cm-disks with nearly 90% of the theoretical density by the SPS process. The resulting disks were consisted of ITO and InOF, and the fluorine content was about 4 at.%. Using the F-ITO disks as sputtering target, thin films were deposited on the glass substrates. The electrical conductivity and optical transmission of the deposited films were comparable to those of the conventional ITO films, while the surface roughness of the films was much improved.     

射频磁控溅射法制备FC/ZnO杂化材料及其基本性质

采用射频磁控溅射法,首先以聚四氟乙烯（PTFE）为靶,氩气为载气,在聚对苯二甲酸乙二醇酯（PET）基底上沉积氟碳（FC）膜;然后以金属锌为靶,氩气为载气,氧气为反应气体,在FC膜上再沉积一层ZnO膜而形成FC/ZnO有机-无机纳米杂化材料。用AFM、XPS、UV以及静态接触角测定仪对杂化材料的基本性质进行了研究。结果表明,该法制得的杂化材料是由纳米粒子组成的岛状结构,岛的表面起伏不平。其生长模式是一种依附于有机核的沉积-扩张生长。杂化材料具有较好的紫外吸收特性,这是由于其分子结构中含有π-π共轭双键、表面的不平整性以及纳米氧化锌粒子对紫外光的吸收共同作用的结果。静态水接触角均大于90°,呈现出良好的疏水性。     

Effect of the Growth Parameters on Nonlinear Optical Properties of Al‐Doped ZnO Nano Films

The objective of this research work is to provide a systematic method to perform test and evaluation on the nonlinear optical properties of Al‐doped ZnO nano thin film structure for designing a high‐performance optical‐electronic structure. Some different kinds of samples can be manufactured for testing. The samples are designed by changing technical parameters such as sputtering power of Al and ZnO, pressure and sputtering time and each parameter has three levels. The test results show that the main factor is the sputtering power of Al, which means the doping density of Al. In the meantime, the Maxwell–Garnett theory is used to investigate the optical prosperities of Al‐doped ZnO nano thin films in the visible range. The optical band gap of Al‐doped ZnO nano thin films increases with the increasing of Al doping density, but it becomes slowly when the doping density is more than 16.0%. The results and the investigation method are useful for designing and manufacturing for nano thin films.     

Photoluminescence Study of Deep Level Defects in ZnO Thin Films

Silicon - In the present work, zinc oxide (ZnO) thin films were prepared by heating, at 500 ∘C, metallic Zn films deposited onto Si (100) substrates by RF magnetron sputtering. According to...     

Effect of annealing and room temperature sputtering power on optoelectronic properties of pure and Al-doped ZnO thin films

Transparent ZnO and Al-doped ZnO (AZO) thin films have been prepared by radio frequency sputtering deposition at room temperature. The optical, electrical, and structural characteristics of the obtained films have been extensively investigated as a function of sputtering and annealing parameters. Spectrophotometry, X-ray diffraction (XRD), atomic force microscopy (AFM), four-point probe and Hall-effect measurements were employed. The ZnO films generally exhibited excellent crystalline properties, while providing a UV cut-off in the absorption spectrum for optical filtration. AZO thin films exhibited an average transparency (larger than 85%) over the visible region of the spectrum, and resistivity of the order of 10^?3 Ω cm was obtained. The carrier concentration and electron mobility values proved to be dependent on the deposition parameters and annealing temperature. The obtained results showed that annealing temperatures higher than 400 °C were not necessary and potentially degraded the electronic properties of the AZO thin films.     

ZnO:Al thin films from (Al2O3)x(ZnO)(1-x) powder targets by magnetron sputtering

In the present work we prepared Aluminum doped Zinc Oxide (AZO) thin films from powder targets. Various concentrations (W/W percentages) of Al₂O₃ such as1%, 2%, 3%, 4%, 5%, 6%, 7% and 8% were mixed in ZnO powder and made in the form of a 3 inch disc target. These ceramic targets are sputtered in RF magnetron sputtering unit for the deposition of AZO thin films. Optical and electrical properties are analyzed to get an optimized percentage of mixing for achieving high transparency and low resistivity. At Al₂O₃ percentage of 3% there is a considerable decrement in the resistivity, and at 7% there is a considerable decrease in the optical transmittance. Mobility and carrier concentration are increasing with Al₂O₃ percentage. Bandgap of the films is observed to be decreasing with increasing the Al₂O₃ percentage.     

Effects of NIR annealing on the characteristics of al-doped ZnO thin films prepared by RF sputtering

Aluminum-doped zinc oxide (AZO) thin films have been deposited on glass substrates by employing radio frequency (RF) sputtering method for transparent conducting oxide applications. For the RF sputtering process, a ZnO:Al₂O₃ (2 wt.%) target was employed. In this paper, the effects of near infrared ray (NIR) annealing technique on the structural, optical, and electrical properties of the AZO thin films have been researched. Experimental results showed that NIR annealing affected the microstructure, electrical resistance, and optical transmittance of the AZO thin films. X-ray diffraction analysis revealed that all films have a hexagonal wurtzite crystal structure with the preferentially c-axis oriented normal to the substrate surface. Optical transmittance spectra of the AZO thin films exhibited transmittance higher than about 80% within the visible wavelength region, and the optical direct bandgap (E_g) of the AZO films was increased with increasing the NIR energy efficiency.     

Effects of power and temperature on the structural,anti-icing,wettability, and optical properties of zinc oxide thin films

Zinc oxide semiconductors have received significant research attention over the past decade owing to their diverse applications. In this paper, we report the development and characterisation of ZnO thin films prepared by radio-frequency (RF) magnetron sputtering. The optical, anti-icing, wettability, and structural properties of the films were investigated at various sputtering power levels and temperatures. With an increase in the power from 175 to 250 W, the ZnO thin films showed fine (002) structures. X-ray diffraction analysis of the coated thin films revealed a considerable increase in the (002) peak intensity along the c-axis with increasing power and temperature. Increasing the sputtering power from 175 to 250 W and the deposition temperature from 150 to 300 °C led to an increase in the average size of the grains from 10.548 to 13.151 nm and from 9.97 to 13.151 nm, respectively. The water contact angle possibly depends on the RF power and temperature employed for material deposition. Within the 350–800 nm range, the prepared films achieved optical transmissions of 92%–88%, refractive indices of 1.52–1.50, and band gaps of 3.28–3.24 eV. The anti-icing properties were also improved by adjusting the sputtering power and temperature during material deposition.     

薄膜厚度对Al掺杂ZnO薄膜性能的影响

采用直流磁控溅射技术,以氧化锌铝陶瓷靶为靶材,在玻璃衬底上制备了ZnO：Al（ZAO）薄膜样品。在其他参数不变的情况下,由不同溅射时间得到了不同厚度的薄膜,研究了薄膜的结构性质、电学和光学性质随薄膜厚度的变化关系。实验结果表明：在薄膜厚度为500 nm时,ZAO薄膜具有最优化的光电性能,电阻率为1.68×10-3Ω.cm,可见光区平均透射率为90.3%。     

Effects of electron doping on the d0 magnetism in N-implanted ZnO and ZnAlO films

In this paper, N ions are implanted into ZnO and ZnAlO films with different carrier concentrations prepared by radio frequency reactive magnetron sputtering on sapphire substrates. The structural, electrical, optical and magnetic properties of N-doped and (Al, N) co-doped ZnO films is investigated, and the particular emphasis is placed on the effects of carrier concentration on the defects induced magnetism in the films. Our results show that all the doped ZnO films are ferromagnetic at room temperature. A trace amount of additional Al doping has a significant effect on the improvement of ferromagnetic properties, and a maximum saturation magnetization of 73 emu/cm³ is obtained for (Al, N) co-doped ZnO films. The optical band gaps of ZnO films increase with the increasing Al doping content, which is owing to the combined effect of high carrier concentration and the Burstein Moss effect. The average transmittance of all ZnO films exceeds 80%. Our results confirm that appropriate electron doping can effectively enhance the magnetic moment in N implanted ZnO which may also apply to other ZnO systems with d⁰ magnetism.     

Study of a sandwich structure of transparent conducting oxide films prepared by electron beam evaporation at room temperature

ABSTRACT: Transparent conducting ZnO/Ag/ZnO multilayer electrodes having electrical resistance much lower than that of widely used transparent electrodes were prepared by ion-beam-assisted deposition (IAD) under oxygen atmosphere. The optical parameters were optimized by admittance loci analysis to show that the transparent conducting oxide (TCO) film can achieve an average transmittance of 93%. The optimum thickness for high optical transmittance and good electrical conductivity was found to be 11 nm for Ag thin films and 40 nm for ZnO films, based on the admittance diagram. By designing the optical thickness of each ZnO layer and controlling process parameters such as IAD power when fabricating dielectric-metal-dielectric films at room temperature, we can obtain an average transmittance of 90% in the visible region and a bulk resistivity of 5 x 10^-5 ohm-cm. These values suggest that the transparent ZnO/Ag/ZnO electrodes are suitable for use in dye-sensitized solar cells.     

Two-step sintering of aluminum-doped zinc oxide sputtering target by using a submicrometer zinc oxide powder

Aluminum-doped zinc oxide (AZO) is a potential substitute for tin-doped indium oxide due to its versatility. The properties of AZO films are related to those of the AZO sputtering target. To improve the performances of AZO targets, two-step sintering was used to densify a submicrometer zinc oxide (ZnO) powder with a size of 0.4 μm to produce both AZO and ZnO targets.     

Nucleant layer effect on nanocolumnar ZnO films grown by electrodeposition

Different ZnO nanostructured films were electrochemically grown, using an aqueous solution based on ZnCl₂, on three types of transparent conductive oxides grow on commercial ITO (In₂O₃:Sn)-covered glass substrates: (1) ZnO prepared by spin coating, (2) ZnO prepared by direct current magnetron sputtering, and (3) commercial ITO-covered glass substrates. Although thin, these primary oxide layers play an important role on the properties of the nanostructured films grown on top of them. Additionally, these primary oxide layers prevent direct hole combination when used in optoelectronic devices. Structural and optical characterizations were carried out by scanning electron microscopy, atomic force microscopy, and optical transmission spectroscopy. We show that the properties of the ZnO nanostructured films depend strongly on the type of primary oxide-covered substrate used. Previous studies on different electrodeposition methods for nucleation and growth are considered in the final discussion.     

Electrical Properties of Gallium-Doped Zinc Oxide Films Prepared by RF Sputtering

Ga-doped polycrystalline ZnO films on glass substrates were prepared by sputtering the targets, which had been prepared by sintering disks consisting of ZnO powder and various amounts of Ga₂O₃, to investigate the effects of gallium doping and sputtering conditions on electrical properties. Optimizing the RF power density, argon gas pressure, and gallium content, transparent Ga-doped ZnO films with resistivity less than 10⁻³Ω·cm were obtained. Electron concentrations for undoped and Ga-doped ZnO films were on the order of 10¹⁸ and 10²¹/cm³, respectively. The Ga-doped ZnO films became degenerate when the electron concentration exceeded ∼ 10¹⁹/cm³, and the optical band gap increased with increasing carrier concentration because of the increase of Fermi energy in the conduction band.     

Sputtered AZO Thin Films for TCO and Back Reflector Applications in Improving the Efficiency of Thin Film a-Si:H Solar Cells

We report the properties of Al doped ZnO (AZO) thin films on glass substrates and its effect on the efficiency of amorphous silicon (a-Si:H) solar cells as the back reflector. Oriented AZO thin films were grown using DC magnetron sputtering by varying Ar gas flow rates. The influence of Ar flow rate on the structural, electrical and optical properties of AZO thin films suitable for transparent conducting oxide (TCO) and back reflector applications was investigated. The (a-Si:H) solar cells, with and without AZO back reflector, were fabricated on FTO coated glass substrates using the PECVD technique. The solar cells were tested using a Sun simulator under AM 1.5 condition. Enhancement in current density from 12.46 to 14.24 mA/cm² with the AZO back reflector was observed, thereby increasing the efficiency of the solar cell from 6.38 to 7.82 %, respectively.     

The evolution behavior of microstructures and optical properties of ZnO films using a Ti buffer layer

ZnO thin films without and with Ti buffer layer were prepared on Si and glass substrates by radio frequency (RF) magnetron sputtering. The effects of Ti buffer layer with different sputtering time on the microstructure and optical properties of ZnO thin films had been investigated by means of X-ray diffraction (XRD), energy dispersive spectrometer, X-fluorescence spectrophotometer and ultraviolet–visible spectrophotometer. The XRD results showed that the full-width at half-maximum (FWHM) for the ZnO (002) diffraction peak gradually decreased with the increase of sputtering time of Ti buffer layer, indicating that the crystalline quality of ZnO thin films was improved. The UV peak located at 390 nm, two blue peaks located at about 435 and 487 nm, two green peaks located at about 525 and 560 nm were observed from PL spectra. The PL spectra showed that the strongest blue light emission of ZnO films was obtained from Ti buffer layer with the sputtering time of 10 min. Meanwhile, the origins of the emission peaks were discussed through the Gaussian deconvolution. We also studied the optical band gaps.     

磁控溅射法制备铁氧体薄膜的磁性能研究

采用溶胶-凝胶法制备纳米晶镍锌钴铁氧体/二氧化硅复合粉体,并将该粉体制成靶材.采用磁控溅射法在单晶硅基底和玻璃基底上沉积镍锌钴铁氧体复合薄膜,并对其进行磁性能研究.研究结果表明:镍锌钴铁氧体/二氧化硅复合薄膜具有较好的软磁性能;在相同的溅射条件下,两种基片上的薄膜的矫顽力都较小,但硅基片上薄膜的饱和磁化强度较玻璃基片上的大,软磁性能更好;经后退火处理,薄膜的饱和磁化强度得到明显地提高,软磁性能得到改善.     

Physical properties of metal-doped zinc oxide films for surface acoustic wave application

Metal-doped ZnO [MZO] thin films show changes of the following properties by a dopant. First, group III element (Al, In, Ga)-doped ZnO thin films have a high conductivity having an n-type semiconductor characteristic. Second, group I element (Li, Na, K)-doped ZnO thin films have high resistivity due to a dopant that accepts a carrier. The metal-doped ZnO (M = Li, Ag) films were prepared by radio frequency magnetron sputtering on glass substrates with the MZO targets. We investigated on the optical and electrical properties of the as-sputtered MZO films as dependences on the doping contents in the targets. All the MZO films had shown a preferred orientation in the [002] direction. As the quantity and the variety of metal dopants were changed, the crystallinity and the transmittance, as well as optical band gap were changed. The electrical resistivity was also changed with changing metal doping amounts and kinds of dopants. An epitaxial Li-doped ZnO film has a high resistivity and very smooth surface; it will have the most optimum conditions which can be used for the piezoelectric devices.