Preparation and Characterization of ZnO:In Transparent Conductor by Low Cost Dip Coating Technique (original) (raw)
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Materials Science-Poland,, 2018
Heavily In doped zinc oxide (IZO) thin films were deposited on glass substrates by dip-coating method with different concentrations of indium. The effect of heavy In doping on the structural, morphological, optical and electrical properties of ZnO was discussed on the basis of XRD, AFM, UV-Vis spectra and Hall effect measurements. The diffraction patterns of all deposited films were indexed to the ZnO wurtzite structure. However, high In doping damaged the films crystallinity. The highest optical transmittance observed in the visible region (>93 %) exceeded that of ITO: the absolute rival of the most commercial TCOs. The grain size significantly decreased from 140 nm for undoped ZnO to 17.1 nm for IZO with the greatest In ratio. The roughness decreased with increasing In atomic ratio, indicating an improvement in the surface quality. Among all synthesized films, the sample obtained with 11 at.% indium showed the best TCO properties: the highest transmittance (93.5 %) and the lowest resistivity (0.41 Ωcm) with a carrier concentration of 2.4 × 10 17 cm −3. These results could be a promising solution for possible photonic and optoelectronic applications.
ZnO Thin Film Deposition for TCO Application in Solar Cell
ZnO is a well known suitable candidate for the Transparent Conducting Oxide (TCO) layer of thin film compound solar cells. In this paper we have discussed the deposition of ZnO thin film on glass substrate by reactive DC magnetron sputtering using Oxygen as a reactive gas. Samples are prepared by varying Oxygen flow rates during the deposition process. After deposition, samples are annealed at 300 oC for 2 hours in vacuum environment. All the properties of the film are measured before and after annealing. All the samples are tested for the optical transparency, band gap and electrical resistivity before and after annealing. Band gap of film is observed 3.2 eV. XRD and SEM measurements of the samples show the variation in the crystal structure and surface morphology of the film with varying oxygen flow rate and annealing also. Around 600 nm thick ZnO film with 1.5x10-3 Ω-cm resistivity and 80% transparency without any doping is achieved.
Optik, 2018
In this work, we have successfully prepared the highly conducting and transparent In doped ZnO thin films on glass substrate using sol-gel spin-coating technique. Indium was incorporated with different concentrations of 1, 2, and 4 at. %. The effect of Indium doping on the structural, optical and electrical properties of the produced films have been investigated. X-ray diffraction analysis showed that all the films were polycrystalline with a hexagonal würtzite structure.The growth along (002) orientation was only preferred for 2 at.% doping concentration. The transparency of In doped ZnO thin films varied from 70 to 92 % in visible range. Zinc oxide thin film doped with 4 at.% concentration revealed the largest grain size, the lowest optical gap, the highest intrinsic defects amount, and the lowest resistivity which was found to be 6.10×10-4 Ω.cm. These In doped ZnO thin films can have big interest in solar cell industry.
2020
This study carried out on the effect of precursor concentration and annealed substrate temperature on the crystal structure, electronic and optical properties of ZnO thin film. An aqueous solution of Acid Nitrite was used as precursors and its concentration was varied from 0.1 M to 0.4 M. The ZnO thin film was deposited on the glass substrate by Spray Pyrolysis Deposition and annealed with different temperature from 300 o C to 600 o C. The crystal structure, electronic and optical properties were investigated by Scanning Electron Microscopy (SEM), X-ray diffraction (XRD) and UV-Spectrometer. XRD result showed that all thin films have amorphous hexagonal wurtzite crystalline. Particle sizes ranging from 21.83 to 43.67 nm were calculated through Debye-Scherer Method. It showed that the concentration of the precursor had slightly impact on the particle size. Meanwhile, the increase in particle size with increasing annealed temperature is found to be gradual. The average transparent of ...
THIN FILM DEPOSITION OF TRANSPARENT CONDUCTIVE OXIDES FOR SOLAR CELL APPLICATION
The present study reports on the physical properties, status, prospects for further development, and applications of polycrystalline or amorphous, transparent, and conducting oxides (TCO) semiconductors. The coexistence of electrical conductivity and optical transparency in these materials depends on the nature, number, and atomic arrangements of metal cations in crystalline or amorphous oxide structures, on the resident morphology, and on the presence of intrinsic or intentionally introduced defects. The important TCO semiconductors are impurity-doped ZnO, In2O3, SnO2 and CdO, as well as the ternary compounds Zn2SnO4, ZnSnO3, Zn2In2O5, Zn3In2O6, In2SnO4, CdSnO3, and multi-component oxides consisting of combinations of ZnO, In2O3 and SnO2. Sn doped In2O3 (ITO) and F doped SnO2 TCO thin films are the preferable materials for most present applications. The expanding use of TCO materials, especially for the production of transparent electrodes for optoelectronic device applications, is endangered by the scarcity and high price of In. This situation drives the search for alternative TCO materials to replace ITO. The electrical resistivity of the novel TCO materials should be ~10-5 Ω.cm, typical absorption coefficient smaller than 104 cm-1 in the near UV and visible range, with optical band gap ~3 eV. At present, ZnO:Al and ZnO:Ga (AZO and GZO) semiconductors could become good alternatives to ITO for thin-film transparent electrode applications. The best candidates are AZO thin films, which have low resistivity of the order of 10−4Ω.cm, inexpensive source materials, and are non-toxic. However, development of large area deposition techniques are still needed to enable the production of AZO and GZO films on large area substrates with a high deposition rate. In addition to the required electrical and optical characteristics, applied TCO materials should be stable in hostile environment containing acidic and alkali solutions, oxidizing and reducing atmospheres, and elevated temperature. Most of the TCO materials are n-type semiconductors, but p-type TCO materials are researched and developed. Such TCO include: ZnO:Mg, ZnO:N, IZO, NiO, NiO:Li, CuAlO2, Cu2SrO2, and CuGaO2 thin films. At present, these materials have not yet found place in actual applications.
Electrical and optical properties of Zn–In–Sn–O transparent conducting thin films
Thin Solid Films
Indium tin oxide (ITO) is one of the widely used transparent conductive oxides (TCO) for application as transparent electrode in thin film silicon solar cells or thin film transistors owing to its low resistivity and high transparency. Nevertheless, indium is a scarce and expensive element and ITO films require high deposition temperature to achieve good electrical and optical properties. On the other hand, although not competing as ITO, doped Zinc Oxide (ZnO) is a promising and cheaper alternative. Therefore, our strategy has been to deposit ITO and ZnO multicomponent thin films at room temperature by radiofrequency (RF) magnetron cosputtering in order to achieve TCOs with reduced indium content. Thin films of the quaternary system Zn-In-Sn-O (ZITO) with improved electrical and optical properties have been achieved.
Annealing effect on properties of transparent and conducting ZnO thin films
This work presents the effect of postdeposition annealing on the structural, electrical and optical properties of undoped ZnO (zinc oxide) thin films, prepared by radio-frequency sputtering method. Two samples, 0.17 and 0.32 µm-thick, were annealed in vacuum from room temperature to 350 °C while another 0.32 µm-thick sample was annealed in air at 300 °C for 1 h. X-ray diffraction analysis revealed that all the films had a c-axis orientation of the wurtzite structure normal to the substrate. Electrical measurements showed that the resistivity of samples annealed in vacuum decreased gradually with the increase of annealing temperature. For the 0.32 µm-thick sample, the gradual decrease of the resistivity was essentially due to a gradual increase in the mobility. On the other hand, the resistivity of the sample annealed in air increased strongly. The average transmission within the visible wavelength region for all films was higher than 80%. The band gap of samples annealed in vacuum increased whereas the band gap of the one annealed in air decreased. The main changes observed in all samples of this study were explained in terms of the effect of oxygen chemisorption and microstructural properties.