Papers by Keyword: ZnO:Al

Abstract: A one-step wet-etching method was developed to prepare the transparent conducting double-layered ZnO:Al films with textured surface for improving the light trapping ability.In this work, we investigated the effects of different deposition and re-deposition conditions including Ar flow rate, working pressure and substrate temperature on the light trapping properties of double-layered ZnO:Al films. Obvious changes for surface morphology of double-layerd films were observed, which displayed the significant influence of the re-deposition process. The double-layered ZnO:Al films presented low resistivity, high optical transmittance and haze value in the visible region, which can meet the requirements of front electrodes.

Abstract: An investigation has been done to study the influence of the Fe and Al doping concentration on the optical properties of zinc oxide thin films. A spray pyrolysis system was used to obtain ZnO:M films doped with Iron and Aluminum, using zinc acetate dihydrate, hydrated iron chlorate and hydrated aluminum chlorate, respectively. The temperature and the concentration were fixed at 450°C and 0.1mol/L, respectively. Our thin films deposed on glass substrate. UV-VIS spectrophotometer has been used for the layers characterization. The optical transmittance spectra showed that the 2% Al dopand improves the optical transmittance in the visible that the Fe dopand. Zinc oxide thin films is the n type semiconductor with direct optical band gap varied between 3.219-3.346eV for obtain the films in photovoltaic application. But the urbach energy of ZnO thin films undoped and doped by Iron and Aluminum is varied between 101– 202 meV.

Abstract: The ZnO:Al (AZO) films were deposited on glass substrates with Al₂O₃ buffer layers by RF magnetron sputtering. The obtained films had the hexagonal structure and preferred orientation of (002). Compared with AZO film without buffer layer, the grain size of the film with buffer layer was increased and the conductive property was increased greatly. the grain size of AZO films reached 27.9nm for those with buffer layers. The optical property of AZO films was decreased by the buffer layers. The resistivity of AZO films with Al₂O₃ buffer layer was about 6.6×10^-3 Ω·cm and the average transmittance was over 80% in the range of 450~900nm.

Abstract: Aluminum doped zinc oxide (ZnO:Al) thin films were deposited on corning glass substrates using DC magnetron sputtering at various growth temperatures (27°C-400°C). X-rays diffraction spectroscopy (XRD) analysis showed the crystal structure of ZnO:Al thin films is wurtzite with c-axis orientation. By enhancing the growth temperature, the crystal size and the crystal stress are increase, while the resistivity of films decreases. Crystal size increase from 35 nm to 52 nm, the stress increase from -7.689 GPa to -5.126 GPa, while the resistivity decreases from 6.29 x 10⁴ Ωcm to 4.05 x 10³ Ωcm. Generally, the quality of crystal enhanced as the raising of growth temperature.

Abstract: ZnO: Al film was deposited on TPT substrate with SiO₂ buffer layer by RF magnetron sputtering. The obtained film had a hexagonal structure and highly (002) preferred orientation. The lattice constant distortion of the film with buffer layer was decreased and the compressive stress was 0.779GPa. The carrier concentratio reached to 3.15×10⁺²⁰/cm3. The resistivity of ZAO film with SiO₂ buffer layer was about 9.2×10^-3 Ω·cm and the average transmittance was over 72% in the range of 380~900nm.

Abstract: In this work, it is reported the characterization of the microstructure and electric properties of ZnO:Al thin films produced by magnetron sputtering. An AZOY sputtering target (98 wt% ZnO + 2 wt% Al₂O₃) was used as source material. The microstructure, optical and electrical properties of ZnO:Al thin films were investigated and correlated with substrate deposition temperature and post-annealing temperature. It is demonstrated that the microstructural, electrical and optical properties of the as-deposited thin films are dependent on the substrate temperature. The crystalline texture of ZnO:Al was improved with temperature deposition as shown in the EBSD analysis and X-ray diffraction. ZnO:Al thin film deposited at 250 °C exhibited very good electrical conductivity, as high as 200 S^.cm^-1 with an activation energy of 5.4 meV. As substrate temperature or heat treatment temperature is increased there is an apparent blue-shift on the absorption edge of the transmittance spectra, which can be explained by the Burnstein-Moss effect.

Abstract: ZnO:Al thin films were deposited on low-iron glass substrates (size: 1100×1400 mm2 ) in an in-line sputtering system, using ZnO:Al ceramic targets. The initially smooth films exhibit high transparencies (T≥85% for visible light) and excellent electrical properties (carrier concentration N=3.810×1020cm-3, mobility μ=20.47 cm2/V•s). The films, etched by diluted HCl for different time, appear roughness morphology with suitable angles and crater structure, used for controlling the light scattering properties of the textured ZnO:Al films. Moreover, the electrical properties are not affected by the etching process. Thus, it is possible to optimize separately the electro-optical and light trapping properties. The textured ZnO:Al films (haze 21.2%, 550 nm) were used as front contacts for amorphous silicon thin film solar cells prepared by PECVD, 6.5% conversion efficiency were obtained.

Abstract: Aluminium doped ZnO (ZnO:Al) films were deposited on polymer substrates by RF magnetron sputtering. The effects of deposition temperatures on structure and properties of films were investigated by X-ray diffractometery, Scanning electronic microscopy, UV-visible spectrophotometer, as well as Four-point Probes System. The results revealed that moderate deposition temperature was helpful to improve the crystal quality and optoelectronic properties of ZnO:Al films. The lowest resistivity of 9.5×10^-3Ω•cm and the average transmittance of 76% in the visible region was obtained for the film deposited from ZnO:2wt% Al₂O₃ target at 75°C.

Abstract: PVA/ zinc acetate sol–gel were fabricated into thin PVA/ zinc acetate composited fibers films by using electrospinning technique. After annealing of the above precursor fibers, ZnO:Al nanofibers with a diameter of 100-700 nm and high length-diameter ratio were obtained successfully. The ZnO:Al nanofibers were characterized by XRD, SEM, and PL, respectively. The XRD results show that Al-doped ZnO nanofibers present ZnO hexagonal structure. PL spectra display that the ZnO: Al nano-fibers have a strong UV emission properties.

Abstract: Transparent conducting zirconium-doped zinc oxide (ZnO:Zr) and aluminium-doped zinc oxide (ZnO:Al) thin films were deposited on glass substrates by direct current (DC) magnetron sputtering at room temperature. The crystallinity of ZnO:Zr and ZnO:Al thin films increases as the target-to-substrate distance decreases, and the crystallinity of ZnO:Zr films is found to be always better than that of ZnO:Al films prepared under the same deposition conditions. As the target-to-substrate distance decreases, the resistivity of both film types decreases greatly while the optical transmittance does not change much with the variation of the distance. When target-to-substrate distance is 4.1 cm, the lowest resistivity of 6.0×10^-4 Ω·cm and 5.7×10^-4 Ω·cm was obtained for ZnO:Zr and ZnO:Al films, respectively. The figure of merit arrived at a maximum value of 3.98×10^-2 Ω for ZnO:Zr films lower than 5×10^-2 Ω for ZnO:Al films.