Investigation of annealing effects on sol–gel deposited indium tin oxide thin films in different atmospheres

Alam, Mohammad Jahangir; Cameron, D.C.

doi:10.1016/s0040-6090(02)00737-x

Cited by 159 publications

(81 citation statements)

References 27 publications

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“…The non-calcined and amorphous films exhibited no measurable electrical conductivity but the sheet resistance substantially decreased to about 3 × 10 5 X upon crystallization and calcination at 450°C. Moreover, the increased concentration of free charge carriers resulting from the formation of oxygen vacancies, [15,16] achieved by treating the films in a reducing atmosphere of nitrogen or hydrogen at 300-450°C, led to a decrease in the film resistance to 1 × 10 4 or 1.3 × 10 3 X, respectively, the latter corresponding to a specific resistivity of 0.02 X cm for 140-150 nm thick films. Hence, in spite of their highly developed 3D mesoporosity, the conductivity of these ITO layers was comparably high and only 1-2 orders of magnitude lower than that of compact films.…”

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confidence: 99%

Transparent Conducting Films of Indium Tin Oxide with 3D Mesopore Architecture

et al. 2006

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Transparent conducting oxides (TCOs) with a well-defined mesoporous framework are of considerable interest for applications in optoelectronic, electrochromic, and electroluminescent devices, solar cells, and sensors. It is the unique combination of transparency, high conductivity, well-defined 3D mesoporosity and high surface area that allows the incorporation of optoelectroactive species, facilitates electron transport to these centers, and efficiently harvests the electron-induced optical response or, vice versa, the photon-induced electron flow. These features would allow and facilitate the further development of dye-sensitized solar cells (DSSCs). However, such conducting transparent frameworks with nanometer-scale periodicity have not been accessible yet, being available solely as nonporous and macroporous layers or powders. [1][2][3] The generation of indium tin oxide (ITO) with well-ordered accessible mesoporosity and high conductivity has not been accomplished yet, partly because of the necessity of high crystallinity, which is indispensable for good electrical conductivity but inconsistent with organized 3D mesoporosity. Recently, the preparation of such mesoporous material was attempted by deposition of ITO onto porous glass substrates, providing composites with an inhomogeneous distribution of ITO. [4,5] Generally, sol-gel techniques are more advantageous for the preparation as they are applicable to various metal oxides and different types of substrates, require mild preparation conditions and, most importantly, allow the control of porosity by appropriate structure-directing agents such as self-organized surfactant micelles from block copolymers. Only a few template-assisted sol-gel syntheses using ITO have been reported, providing powders with quite high resistivity [6] or materials with irregular porosity resulting from the loose packing of crystallites. [7,8] Hence, subsequent functionalization of such material is significantly impeded. Mesoporous powders and macroporous films of undoped indium oxide were produced by sol-gel processes, but the resistivity of such material is usually too high for practical applications. [3,9] In general, the synthesis of films is aggravated by the rather poor ability of indium compounds to form stable sols and the difficulty in controlling the crystal growth of ITO. Using evaporation-induced self-assembly (EISA), various metal oxides (in particular, TiO 2[10]) have recently been obtained as crystalline thin films with ordered 3D mesoporosity. However, this technique has not been applied to certain metal oxides, particularly ITO, because of the breakdown of the mesostructure upon crystallization. The need of suitable block-copolymer templates was identified as one of the key features in the synthesis of mesoporous films with high crystallinity. [11] Owing to a new type of block copolymers with vastly improved structure-directing properties (poly(ethylene-co-butylene)-b-poly(ethylene oxides), referred to as "KLEs"), [12] we have overcome the collapse of the mesoscopi...

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Transparent Conducting Films of Indium Tin Oxide with 3D Mesopore Architecture

et al. 2006

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“…In general, the electrical conductivity of the ITO thin films with a fixed Sn dopant concentration is determined by the oxygen vacancies and the grain size, which are responsible for the carrier density and mobility, respectively. In other reports, 3,18 a decrease in the sheet resistance with an increasing annealing temperature was attributed to the grain growth or crystallinity of ITO films. In these samples, such crystallinity enhancement was detected only for the annealed ITO layers on glass substrates, so it is thought that the conductivity increase was mainly due to the increment in the carrier concentration, especially for the ITO layers deposited onto the polyimides.…”

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confidence: 83%

Thin‐film polyimide/indium tin oxide composites for photovoltaic applications

Lozano¹,

Abajo²,

Campa³

et al. 2006

J of Applied Polymer Sci

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Soluble polyimides were prepared from suitable monomers and were evaluated for their thermal and mechanical properties. The polymers were processed into films for use as supports for transparent, conductive indium tin oxide (ITO) layers. After deposition, annealing in vacuo at temperatures up to 4008C was performed to test the ability of the materials to endure typical device fabrication temperatures without damage to the ITO-coated polymeric substrate. The evolution of the structural, optical, and electrical characteristics with the annealing temperature was analyzed and compared with that of polymeric and conventional glass substrates as references. Polyimide 6F6F, synthesized from hexafluoroisopropylidene diphthalic dianhydride and hexafluoroisopropylidene dianiline, had optimal characteristics for photovoltaic applications, permitting the achievement of conductive, ITO-coated samples with optical transmission greater than 75% in the visible and nearinfrared wavelength ranges, without significant deterioration of their properties after vacuum annealing at temperatures up to 3508C.

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“…The high optical transmittance of these two films was mainly attributed to the expansion of the gain size and the predominant gain orientation (along (400) plane), which are revealed by Table 1 and XRD patterns. From the transmittance spectra in the ultraviolet region, the ITO film absorption coefficient α can be calculated using the following equation [20]:…”

Section: Structural Properties Of Ito Thin Filmsmentioning

confidence: 99%

Effect of surfactants on the structure and photoelectric properties of ITO films by sol-gel method

Liu

Zhang

et al. 2010

Rare Metals

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The Indium tin oxide (ITO) thin film possesses excellent photoelectric properties that enable it to act as an ideal transparent conductor. To obtain high-quality ITO films through sol-gel method, the ionic surfactant monoethanolamine and the non-ionic surfactant polyethylene glycol (PEG) were added to the ITO precursor slurry. The influences of surfactants on the structural and photoelectric properties of ITO film samples were investigated. XRD patterns indicated that surfactant monoethanolamine contributed to film predominant grain orientation along the (400) plane. The high transmittance (over 95%) was attributed to the preferred orientation and the grain size expansion of ITO films. SEM showed that the surface particle size and the morphology of ITO films were strongly dependent on the kind of surfactants used. Moving to the shortwave region, the absorption edge of the films exhibited the Burstein-Moss shift.

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Investigation of annealing effects on sol–gel deposited indium tin oxide thin films in different atmospheres

Cited by 159 publications

References 27 publications

Transparent Conducting Films of Indium Tin Oxide with 3D Mesopore Architecture

Transparent Conducting Films of Indium Tin Oxide with 3D Mesopore Architecture

Thin‐film polyimide/indium tin oxide composites for photovoltaic applications

Effect of surfactants on the structure and photoelectric properties of ITO films by sol-gel method

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