Substrate temperature and thickness dependence of properties of boron and gallium co-doped ZnO films
TL;DR: In this paper, the dependence of structural, electrical and optical properties on the thickness and substrate temperature of transparent conducting oxide films of boron and gallium co-doped ZnO (BGZO) was investigated.
Abstract: Transparent conducting oxide films of boron and gallium co-doped ZnO (BGZO) were prepared on glass substrates by radio frequency magnetron sputtering at room temperature and 200°C, respectively. The dependence of structural, electrical and optical properties on the thickness and substrate temperature were investigated. All films demonstrated c-axis preferred orientation and showed highly transparent in the visible wavelength region. With the increase thickness and substrate temperature, the grain size of BGZO films increased and the full width at half maximum decreased, the carrier mobility increased and resistivity decreased, which indicated that the crystallinity and conductivity of films were improved. The research also found that the optical band gap (Eg) of BGZO thin films decreased with increased substrate temperature and thickness.
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TL;DR: Aluminiumdoped zinc oxide (AZO)/fluorine-doped tin dioxide (FTO) double-layered transparent conducting films were manufactured on quartz glass substrates by spray pyrolysis.
Abstract: Aluminium-doped zinc oxide (AZO)/fluorine-doped tin dioxide (FTO) double-layered transparent conducting films were manufactured on quartz glass substrates by spray pyrolysis. Like top films, AZO ha...
21 citations
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...On the other hand, AZO loses its excellent electrical conductivity when placed in an air atmosphere of over 350°C [8,14]....
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TL;DR: In this paper, a ZnO:Eu film has been deposited and grown on glass substrates by spin coating technique followed by water bath treatment, the precursors were synthesised by a sol-gel method and all of the f...
Abstract: ZnO:Eu film has been deposited and grown on glass substrates by spin coating technique followed by water bath treatment. The precursors were synthesised by a sol–gel method and all of the f...
10 citations
Cites background from "Substrate temperature and thickness..."
...increase in the grain size [28] and oxygen vacancies [23]....
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TL;DR: In this article, the effect of substrate temperature on the energy storage properties of BMNO thin films is investigated systematically, and the X-ray diffraction pattern reveals the thin films are polycrystalline with cubic pyrochlore structure.
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TL;DR: In this article, the optical constants of amorphous Ge were determined for the photon energies from 0.08 to 1.6 eV, and the absorption is due to k-conserving transitions of holes between the valence bands as in p-type crystals.
Abstract: The optical constants of amorphous Ge are determined for the photon energies from 0.08 to 1.6 eV. From 0.08 to 0.5 eV, the absorption is due to k-conserving transitions of holes between the valence bands as in p-type crystals; the spin-orbit splitting is found to be 0.20 and 0.21 eV in non-annealed, and annealed samples respectively. The effective masses of the holes in the three bands are 0.49 m (respectively 0.43 m); 0.04 m, and 0.08 m. An absorption band is observed below the main absorption edge (at 300 °K the maximum of this band is at 0.86 eV); the absorption in this band increases with increasing temperature. This band is considered to be due to excitons bound to neutral acceptors, and these are presumably the same ones that play a decisive role in the transport properties and which are considered to be associated with vacancies. The absorption edge has the form: ω2ϵ2∼(hω−Eg)2 (Eg = 0.88 eV at 300 °K). This suggests that the optical transitions conserve energy but not k vector, and that the densities of states near the band extrema have the same energy-dependence as in crystalline Ge. A simple theory describing this situation is proposed, and comparison of it with the experimental results leads to an estimate of the localization of the conduction-band wavefunctions.
8,184 citations
TL;DR: In this article, the experimental evidence concerning the density of states in amorphous semiconductors and the ranges of energy in which states are localized is reviewed; this includes d.c and a.c. conductivity, drift mobility and optical absorption.
Abstract: The experimental evidence concerning the density of states in amorphous semiconductors and the ranges of energy in which states are localized is reviewed; this includes d.c. and a.c. conductivity, drift mobility and optical absorption. There is evidence that for some chalcogenide semiconductors the model proposed by Cohen, Fritzsche and Ovshinsky (1969) should be modified by introducing a band of localized states, near the centre of the gap. The values of C, when the d.c. conductivity is expressed as C exp (- E/kT), are considered. The behaviour of the optical absorption coefficient near the absorption edge and its relation to exciton formation are discussed. Finally, an interpretation of some results on photoconductivity is offered.
3,465 citations
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...7c, with the same thickness, the optical band gap decreases slightly when substrate temperature increase from RT to 200°C, which is relates to decrease in the carrier concentration blocking the lowest states in the conduction band, well known as the Burstein–Moss effect.(29)...
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3,408 citations
TL;DR: The present status and prospects for further development of polycrystalline or amorphous transparent conducting oxide (TCO) semiconductors used for practical thin-film transparent electrode applications are presented in this paper.
Abstract: The present status and prospects for further development of polycrystalline or amorphous transparent conducting oxide (TCO) semiconductors used for practical thin-film transparent electrode applications are presented in this paper. The important TCO semiconductors are impurity-doped ZnO, In2O3 and SnO2 as well as multicomponent oxides consisting of combinations of ZnO, In2O3 and SnO2, including some ternary compounds existing in their systems. Development of these and other TCO semiconductors is important because the expanding need for transparent electrodes for optoelectronic device applications is jeopardizing the availability of indium-tin-oxide (ITO), whose main constituent, indium, is a very expensive and scarce material. Al- and Ga-doped ZnO (AZO and GZO) semiconductors are promising as alternatives to ITO for thin-film transparent electrode applications. In particular, AZO thin films, with a low resistivity of the order of 10−5 Ω cm and source materials that are inexpensive and non-toxic, are the best candidates. However, further development of the deposition techniques, such as magnetron sputtering or vacuum arc plasma evaporation, as well as of the targets is required to enable the preparation of AZO and GZO films on large area substrates with a high deposition rate.
1,959 citations
TL;DR: In this paper, the authors summarize recent progress in doping control, materials processing methods such as dry etching and Ohmic and Schottky contact formation, new understanding of the role of hydrogen and finally the prospects for control of ferromagnetism in transition-metal doped ZnO.
1,625 citations