Papers by Keyword: Transparent Conducting Oxide (TCO)

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Authors: Prasanta Kumar Biswas
Abstract: Nanostructured transparent conducting oxide (TCO) films such as tin doped indium oxide (ITO), antimony doped tin oxide (ATO), tin doped cadmium oxide (CTO) were deposited on suprasil grade pure silica glass from their respective precursors with wide variation of dopant concentration, 10, 30, 50, 70 at. % and their optical properties have been studied. The films were obtained by thermal curing (350 - 500°C) in air. If the cluster size be decreased to nanoscale then blue shift of bulk band gap occurs due to the quantum confinement effect of the semiconducting TCO materials. Free carrier concentration of ITO and ATO films were in the order of 1019 cc-1. The Moss-Burstein shift occurred in each case. The photoluminescence (PL) behaviour of the nanostructured materials revealed emissions for the HOMO-LUMO excitonic transitions. This was identified by selecting the excitation energy according to the photoluminescence excitonic transitions (PLE).
Authors: Wan Zurina Samad, Mohd Ambar Yarmo, Muhamad Mat Salleh
Abstract: A comparison study on deposition temperature between 40oC and 60oC using new route coating which is inkjet printing technique have been studied in this research paper. The FTO material were prepared by a common mixture technique between precursor solution of SnCl4.5H2O and NH4F as a doping agent. The prepared samples were coated on the glass substrate sized 20mm x 25mm and were calcined at 450oC. The samples were characterized using XRD, XPS, VP-SEM and UV-VIS. From the VP-SEM, the result show the different surface morphology between the two deposition temperatures. Samples prepared at 60oC shows a lot existence some kind of crystal shape on the substrate compared to films deposited at 40oC. Surface studies using XPS technique shows the existence of elements such as Sn, O and F. Detail analysis of these elements shows that Sn 3d5/2 form as Sn-O, O1s as oxygen linkage and F1s as Sn-F. The XPS and XRD results also shows that no significant changes on chemical stoichiometry for both deposition temperatures. The optimum optical properties with lower resistivity were found for thin films deposited at 40oC with 91 %T and 16 Ω/□.
Authors: C.M. Mahajan, A.G. Godbole, S.P. Gumfekar, S.H. Sonawane, M.G. Takwale
Abstract: Nanocrystalline undoped and Al doped ZnO thin films were synthesized by the chemical spray pyrolysis of Zinc acetate and Aluminium chloride solution. The optoelectronic properties of undoped and Al:ZnO films were investigated. The XRD patterns of films were preferably oriented along c-axis [0 0 2] plane with the hexagonal wurtzite structure. The Al-doping caused no additional X-ray diffraction peaks when compared with XRD of undoped film, indicating Al2O3 content was below the detection limit. The crystallite size of undoped and Al doped film was 48 nm and 51nm respectively, as measured from X-ray diffractogram. The films are of high optical transmittance (≥ 90%). The resistivity of the film was found to decrease because of Al doping. The dark resistivity measurement for Al:ZnO film was of the order of 10-3 Ω-1cm-1. The band gap energy of the film was found to vary from 3.25 to 3.32eV indicating the Moss Burstein shift. Al:ZnO films can be used as transparent conducting oxide layers for photovoltaic applications.
Authors: Lin Dong, Teng Fei Pei, Hong Qing Li, Da Yan Xu
Abstract: Transparent conducting Al-doped ZnO films were prepared by ultrasonic spray pyrolysis technique on amorphous glass substrates under atmospheric environment with substrate temperature ranging from 350 to 500 , and Al/ZnO molar ratio of 1, 3 and 5 %. The impacts of the substrate temperature and doping level on structural, optical and electrical properties of the ZnO:Al thin films were investigated. The texture coefficient calculated from XRD data indicates that the substrate temperature at 450 and the doping level of 3 at.% is beneficial for crystal growth along (002) orientation. The Band gap (Eg) and Urbach parameter (E0) deduced by the optical absorption edge increases and decreases with the increase of Al doping level, respectively. The increase in sheet resistance is assumed to be associated with the decrease in preferential orientation and formation of Al2O3-x clusters.
Authors: Soumyadeep Sinha, Shaibal K. Sarkar
Abstract: Zinc Oxide (ZnO) films were deposited by Atomic Layer Deposition (ALD) using Diethylzinc and a combination of Water and Ozone as the precursores. Electrical conductivity of ALD grown ZnO films, under low field, were studied with varied partial pressure of the constituent reactants. Supressing the oxygen vacancy by introducing O3 during the reaction increase the resistivity of the films by couple of orders of magnitude. UV-Vis spectroscopy measurement showed the films to be transparent giving a room for its application as a TCO in solar cell.
Authors: Yue Hui Hu, Hai Jun Xu, Hao Gao, Yi Chuan Chen
Abstract: The pyramid-like textured ZnO film was prepared directly by magnetron sputtering on the self-supporting substrate of ZnO:Al film fabricated by sol-gel. The performance of amorphous silicon solar cell has been studied using the textured ZnO film as a front electrode. It was found that: (1) using the textured ZnO film as an amorphous silicon solar cell front electrode, it can be improved the open voltage, but the fill factor and conversion efficiency was depraved; and (2) inserting a protocrystalline silicon buffer layer between ZnO and p-a-SiC:H, the performance of solar cell was improved obviously. For example, its conversion efficiency increases from 7.3% for the SnO2: FTCO to 7.9% for the ZnO/pc-Si:H TCO.
Authors: Peter Gerhardinger, David Strickler
Abstract: Thin film coatings of fluorine doped tin oxide on glass were first produced in the 1940’s as part of the World War II effort. Generically known as TCO (Transparent Conductive Oxide) Coatings, the primary use was for antifogging coatings for aircraft transparencies using an electrical current to heat the glass assembly. Nearly 60 years later, these coatings are still used in cockpit glazings. Although the first generation coatings were applied using spray pyrolysis on heated glass panes, by 1990 these coatings were being applied directly on the float glass ribbon during the primary glass manufacturing operation, using Atmospheric Pressure Chemical Vapor Deposition (APCVD). As part of a color suppressed multi-layer structure, these coatings met the aesthetic and performance criteria for architectural low E glazings, and spawned new applications in electrochromic devices, heated freezer doors, radiant glass heaters, EMI/RFI Shielding, and the largest growing segment in glass – thin film photovoltaic panels. In this paper we discuss the characteristics of the on-line production, the performance characteristics of the coatings, the end use requirements, and the massive infrastructure in place worldwide to support the volume requirements. We compare the properties of SnO2:F to other emerging TCO materials such as zinc oxide.
Authors: Jian Lin Chen, Yan Jie Ren, Jian Chen, Jian Jun He, Ding Chen
Abstract: Preferentially oriented Al-doped ZnO thin films with doping concentration of 1, 2, 3, 5 and 10 mol% respectively were prepared on glass substrates via sol-gel route. The crystallinity of films was characterized by X-ray diffraction and the surface morphologies were observed by scanning electron microscopy. The results show that ZnO:Al films at low doping concentration (1, 2 mol%) grow into dense homogenous microstructure. However, as for high doping concentration (3, 5, 10 mol%), Al3+ precipitate in the form of amorphous Al2O3 and ZnO:Al films exhibit heterogeneous nucleation and exceptional growth of the big plate-like crystals at the interface of the amorphous Al2O3 and ZnO:Al matrix.
Authors: Eun Soo Lee, Rachmat Adhi Wibowo, Kyoo Ho Kim
Abstract: Al-doped ZnO (AZO) thin films were grown on Corning 1737 glass by RF Magnetron Sputtering under premixed hydrogen-argon (H2/Ar) sputtering gas. It is found that the introduction of various H2 concentrations during sputtering deposition altered the properties of Al-doped ZnO films. The presence of H2 during AZO growth at low deposition temperature leads to the growth of a-axis preferential orientation crystal whereas c-axis preferential orientation occurred only at higher deposition temperature. Highly oriented c-axis (002) crystal has been successfully grown under 3% H2 concentration at 200°C deposition temperature. Film’s resistivity is appeared to be a function of H2 concentration. Additional H2 concentration in sputtering gas increased of film’s transmittance up to 85% at visible-near infra red spectra while it caused the Burstein-Moss shift toward the blue region at 350 nm wavelength.
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