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Ratnabali Banerjee

Bio: Ratnabali Banerjee is an academic researcher from Indian Association for the Cultivation of Science. The author has contributed to research in topics: Thin film & Amorphous silicon. The author has an hindex of 10, co-authored 41 publications receiving 829 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, the magnetron sputtering technique was used to produce highly transparent (transmission ∼90%) and conducting (resistivity ∼10−5 Ω'cm) indium tin oxide (ITO) films.
Abstract: Indium tin oxide (ITO) films have been prepared by the magnetron sputtering technique from a target of a mixture of In2O3 and SnO2 in the proportion 9:1 by weight. By optimizing the deposition conditions it has been possible to produce highly transparent (transmission ∼90%) and conducting (resistivity ∼10−5 Ω cm) ITO films. A resistivity ∼10−4 Ω cm has been obtained for films of thickness ∼1000 A at a comparatively low substrate temperature of 50 °C and without using oxygen in the sputtering chamber. To characterize the films, the following properties have been studied, viz., electrical conductivity, thermoelectric power, Hall effect, optical transmission, and band gap. The effect of annealing in air and vacuum on the properties of the films have also been studied.

304 citations

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TL;DR: In this article, the degradation of tin-doped indiumoxide (ITO) films in glow-discharge plasmas of hydrogen and argon have been investigated, and several parameters have been varied for the study, including the temperature of ITO under ion bombardment, the rf power density, the time of exposure to plasma, and the gas flow rate.
Abstract: The degradation of tin‐doped indium‐oxide (ITO) films in glow‐discharge plasmas of hydrogen and argon have been investigated. Parameters which have been varied for the study include the temperature of ITO under ion bombardment, the rf power density, the time of exposure to plasma, and the gas flow rate. After bombardment, scanning electron micrograph observation, measurement of sheet resistance, transmittance and reflectance, and Auger analysis have been carried out to decide the extent of degradation. Magnetron‐sputtered ITO films have been found to be more resistant to ion bombardment damage compared to electron‐beam evaporated films. The degradation of ITO under the plasma of the reducing species such as hydrogen has been found to take place at lower temperature and power density compared to argon plasma.

99 citations

Journal ArticleDOI
TL;DR: In this paper, a transparent conducting thin films of tin oxide were prepared by electron beam evaporation of sintered pellets of SnO 2 under controlled conditions, and structural, electrical and optical properties were measured to characterize the films.

93 citations

Journal ArticleDOI
TL;DR: Tin oxide films were prepared by electron beam evaporation of pellets of Specpure SnO2 in the presence of added oxygen as mentioned in this paper, and by optimizing the deposition conditions, transparent and conducting tin oxide films exhibiting the structural characteristics of a predominant SnO 2 phase were produced.

68 citations

Journal ArticleDOI
TL;DR: In this article, the authors used X-ray diffraction and transmission electron microscopy to characterize the resistivity, Hall effect, transmittance and optical band gap of ITO films.

54 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, the authors reviewed work on In2O3:Sn films prepared by reactive e−beam evaporation of In2 O3 with up to 9 mol'% SnO2 onto heated glass.
Abstract: We review work on In2O3:Sn films prepared by reactive e‐beam evaporation of In2O3 with up to 9 mol % SnO2 onto heated glass. These films have excellent spectrally selective properties when the deposition rate is ∼0.2 nm/s, the substrate temperature is ≳150 °C, and the oxygen pressure is ∼5×10−4 Torr. Optimized coatings have crystallite dimensions ≳50 nm and a C‐type rare‐earth oxide structure. We cover electromagnetic properties as recorded by spectrophotometry in the 0.2–50‐μm range, by X‐band microwave reflectance, and by dc electrical measurements. Hall‐effect data are included. An increase of the Sn content is shown to have several important effects: the semiconductor band gap is shifted towards the ultraviolet, the luminous transmittance remains high, the infrared reflectance increases to a high value beyond a certain wavelength which shifts towards the visible, phonon‐induced infrared absorption bands vanish, the microwave reflectance goes up, and the dc resisitivity drops to ∼2×10−4 Ω cm. The corre...

2,124 citations

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TL;DR: This review explores different material classes for plasmonic and metamaterial applications, such as conventional semiconductors, transparent conducting oxides, perovskiteOxides, metal nitrides, silicides, germanides, and 2D materials such as graphene.
Abstract: Materials research plays a vital role in transforming breakthrough scientific ideas into next-generation technology. Similar to the way silicon revolutionized the microelectronics industry, the proper materials can greatly impact the field of plasmonics and metamaterials. Currently, research in plasmonics and metamaterials lacks good material building blocks in order to realize useful devices. Such devices suffer from many drawbacks arising from the undesirable properties of their material building blocks, especially metals. There are many materials, other than conventional metallic components such as gold and silver, that exhibit metallic properties and provide advantages in device performance, design flexibility, fabrication, integration, and tunability. This review explores different material classes for plasmonic and metamaterial applications, such as conventional semiconductors, transparent conducting oxides, perovskite oxides, metal nitrides, silicides, germanides, and 2D materials such as graphene. This review provides a summary of the recent developments in the search for better plasmonic materials and an outlook of further research directions.

1,836 citations

Journal ArticleDOI
TL;DR: In this article, a detailed description of the conduction mechanism and the main parameters that control the conductivity of ITO films are presented, on account of the large varieties and differences in the fabrication techniques.
Abstract: Tin doped indium oxide (ITO) films are highly transparent in the visible region, exhibiting high reflectance in the infrared region, and having nearly metallic conductivity. Owing to this unusual combination of electrical and optical properties, this material is widely applied in optoelectronic devices. The association of these properties in a single material explains the vast domain of its applicability and the diverse production methods which have emerged. Although the different properties of tin doped indium oxide in the film form are interdependent, this article mainly focuses on the electrical aspects. Detailed description of the conduction mechanism and the main parameters that control the conductivity is presented. On account of the large varieties and differences in the fabrication techniques, the electrical properties of ITO films are discussed and compared within each technique.

876 citations

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TL;DR: Among the available BHJ systems, poly(3-hexylthiophene)(P3HT) and 1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6)C.
Abstract: Despite the relatively low efficiencyin comparison with conventional inorganic solar cells, thepotential of roll-to-roll processing and large-area processa-bility on flexible low-cost substrates renders conjugatedpolymer-based organic solar cells (OSCs) very attractive asa cost-effective solution to the problem of energy shortage.Among the available BHJ systems, poly(3-hexylthiophene)(P3HT) and 1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6)C

844 citations

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TL;DR: In this paper, an indium tin oxide anode contact to an organic light emitting device via oxygen plasma treatment was shown to improve the performance of single-layer doped-polymer devices.
Abstract: We demonstrate the improvement of an indium tin oxide anode contact to an organic light emitting device via oxygen plasma treatment. Enhanced hole-injection efficiency improves dramatically the performance of single-layer doped-polymer devices: the drive voltage drops from >20 to <10 V, the external electroluminescence quantum efficiency (backside emission only) increases by a factor of 4 (from 0.28% to 1%), a much higher drive current can be applied to achieve a much higher brightness (maximum brightness ∼10,000 cd/m2 at 1000 mA/cm2), and the forward-to-reverse bias rectification ratio increases by orders of magnitude (from 102 to 106–107). The lifetime of the device is also enhanced by two orders of magnitude.

734 citations