Periodically structured ZnO thin films for optical gas sensor application

Dikovska, A.; Atanasov, P.A.; Tonchev, S.; Ferreira, João F.; Escoubas, Ludovic

doi:10.1016/j.sna.2007.05.032

Cited by 28 publications

(9 citation statements)

References 11 publications

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“…ZnO-based transparent electrodes have been extensively investigated as potential substitutes 2,3 . Conductive ZnO films have aroused increasing interest due to their applications in solar cells, gas sensors, varistors and light emitting diodes [4][5][6] . However, the electrical conductivity of ZnO is low compared to most TCO electrodes.…”

Section: Introductionmentioning

confidence: 99%

Physical Properties of Sputtered Indium-doped ZnO Films Deposited on Flexible Transparent Substrates

et al. 2018

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Indium-doped zinc oxide (IZO) polycrystalline thin films were grown on polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and as reference on 7059 Corning glass substrates at room temperature by radio frequency magnetron sputtering from a target prepared with a mixture of ZnO and In 2 O 3 powders. The structural, optical, and electrical properties of the films were analyzed and compared. The IZO polycrystalline films showed n-type conductivity. The electrical resistivity drops significantly, and the carrier concentration increases as a consequence of In incorporation within the ZnO crystalline lattice. In both cases the changes are of several orders of magnitude. The resistivity obtained was 3.1 ± 0.5 x 10 -3 Ω-cm for an IZO sample grown on PET with a carrier concentration of 3.1 ± 0.7 x 10 20 cm -3 , the best mobility obtained was 27.7 ± 0.8 cm 2 V -1 s -1 for an IZO sample grown on PEN. From the results, we conclude that n-type IZO polycrystalline films with high transmittance, high mobility and low resistivity were obtained on flexible transparent substrates.

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Section: Introductionmentioning

confidence: 99%

Physical Properties of Sputtered Indium-doped ZnO Films Deposited on Flexible Transparent Substrates

et al. 2018

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“…Due to its remarkable properties such as transparency in VIS and NIR spectral regions, low resistivity, biocompatibility, and long-term stability, ZnO gains increasing scientific interest. Additionally, ZnO is inexpensive and nontoxic and finds diverse applications in the fields of optoelectronics [1], bio and gas sensing [2][3][4], and integrated optical devices [5] and for optically transparent electrodes in flat panel displays [6] or solar cells [7] for self-cleaning coatings [8].…”

Section: Introductionmentioning

confidence: 99%

Effect of Substrate Temperature on the Microstructural, Morphological, and Optical Properties of Electrosprayed ZnO Thin Films

Маринов

Strijkova

Vasileva

et al. 2018

Advances in Condensed Matter Physics

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Polycrystalline ZnO thin films were prepared on silicon substrates using electrospray method with vertical setup. Water and ethanol were used as solvents for zinc acetate dehydrate and no postdeposition annealing was required for formation of ZnO. The influence of substrate temperature in the range of 150–250°C on surface morphology and roughness was studied by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), and optical profilometry. An improvement of surface quality and smoothing of the films with temperature were obtained. X-ray diffraction measurements revealed that, at all investigated substrate temperatures, the films were polycrystalline with crystallites’ sizes decreasing with temperature. Besides, the preferred crystal orientation varies with the substrate temperature. The analysis of surface chemical composition and oxidation state was performed with X-ray photoelectron spectroscopy (XPS). It was shown that, at substrate temperature of 200°C, the deposited ZnO films were closest to the stoichiometric ones. In general, the films at 150°C were oxygen-deficient, while at other studied temperatures, the films had excess of oxygen more pronouncedly at 200°C. Spectral ellipsometric measurements confirmed that the structural disorder is the highest at 150°C and improves with temperature. Refractive indexes for films at 200°C and 250°C are almost the same, 1.97 and 1.93, respectively, at wavelength of 600 nm, while for the sample deposited at 150°C, the refractive index is substantially lower, 1.67. The optical band gap is slightly influenced by the substrate temperature: 3.27 eV at 150°C and 3.32 eV at 200°C.

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“…In turn, relatively few works investigated on the possibility to employ optical detection based on ZnO photoluminescence (PL) [6][7][8][9][10][11][12]. In this regard, it is worth recalling that PL represent both an analytic tool for characterizing the defect composition and/or crystal quality of metal-oxide semiconductors [13][14][15][16] and a mean to monitor the adsorption of gas molecules on light-emitting nanostructures [17,18].…”

Section: Introductionmentioning

confidence: 99%