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1.
Highly transparent, p-type conducting SnO2:Al films derived from thermal diffusion of a sandwich structure Al/SnO2/Al multilayer thin films deposited on quartz substrate have been prepared by direct current and radio-frequency magnetron sputtering using Al and SnO2 targets. The deposited films were annealed at various temperatures for different durations. The effect of thermal diffusing temperature and time on the structural, electrical and optical performances of SnO2:Al films has been studied. X-ray diffraction results show that all p-type conducting films possessed polycrystalline SnO2 with tetragonal rutile structure. Hall-effect results indicate that 450 °C for 4 h were the optimum annealing parameters for p-type SnO2:Al films, resulting in a relatively high hole concentration of 7.2 × 1018 cm?3 and a low resistivity of 0.81 Ω cm. The transmission of the p-type SnO2:Al films was above 80%. 相似文献
2.
《Intermetallics》2015
Measurements of electronic structure, microstructure and thermoelectric properties of zinc antimonide thin films prepared by direct current magnetron co-sputtering were carried out. The as-deposited zinc antimonide thin film had a very high resistivity similar to insulating ceramics, which was due to a low binding energy of both zinc and antimony, with the electron scattering increases and impedes the current transport. With the increase in annealing temperature, the films became more crystalline and the thermoelectric properties were also improved. The resistivity of the film decreased rapidly with its crystallinity when the annealing temperature was above 350 °C. The Seebeck coefficients of the thin films were positive, indicating that the films were P-type. The Seebeck coefficient of those samples increased with increasing annealing temperature. The thin film annealed at 400 °C has an optimal power factor of 1.87 × 10−3 Wm−1 K−2 with a Seebeck coefficient of 300 μVK−1 and a resistivity of 4.82 × 10−5 Ωm at 573 K. 相似文献
3.
Sanghee Won Seunghee Go Wonhee Lee Kyunghoon Jeong Hyunsuk Jung Chongmu Lee Eungu Lee Jaegab Lee 《Metals and Materials International》2008,14(6):759-765
Thin TiO2 layers grown at 130°C on SiO2-coated Si substrates by atomic layer deposition (ALD) using TTIP and H2O as precursors were annealed, and the effects of the annealing temperature on the resulting electrical properties of TiO2 and the interface properties between a Pt electrode and TiO2 were examined using transmission line model (TLM) structures. The as-deposited TiO2 thin film had an amorphous structure with OH groups and a high resistivity of 6×103Ω-cm. Vacuum annealing at 700 °C transformed the amorphous film into an anatase structure and reduced its resistivity to 0.04Ω-cm.
In addition, the vacuum-annealing of the TiO2/SiO2 structure at 700°C produced free silicon at the TiO2-SiO2 interface as a result of the reaction between the Ti interstitials and SiO2. The SiO2 formed on the TiO2 surface caused a Schottky contact, which was characterized by the TLM method. The use of the TLM method enabled the accurate
measurement of the resistivity of the vacuum-annealed TiO2 films and the characterization of the Schottky contacts of the metal electrode to the TiO2. 相似文献
4.
S.H. Mohamed 《Surface & coatings technology》2008,202(10):2169-2175
The studies of thermal stability of nitride coatings are important since their structural, thermal, electrical and optical properties are drastically modified by the oxidation layer formed on the top of these coatings. Tungsten nitride films were deposited from metallic tungsten target using reactive pulsed d. c. magnetron sputtering. The films were annealed in air at different temperatures for 1 h. The structural, electrical resistivity and optical properties of the annealed films were analyzed. Besides the film analysis, powder of tungsten nitride was obtained by scratching the coating from the glass substrates. The oxidation kinetics of the scratched powder was studied using simultaneous thermal gravimetric/deferential thermal analysis measurements. X-ray diffraction patterns revealed that W2N oxidizes to the two different phases WO3 and WO2.92. The oxide diffraction peaks appeared upon annealing at 773 K and the relative intensities increased with annealing temperature. The tungsten nitride was found to oxidize according a parabolic relation between mass gain and oxidation time. The activation energy of oxidation was evaluated by analyzing the Arrhenius relation from the temperature dependence of the weight gain. The obtained value was 1.76 eV. The activation energies of crystallization of the two phases were calculated. The electrical resistivity was found to increase drastically upon oxidation. The optical properties of the films are very sensitive to the oxidation temperature. The optical band gap values for the film oxidized at 773 K and 823 K are 2.71 and 2.58 eV, respectively. 相似文献
5.
Transparent p-type conducting SnO2/Al/SnO2 multilayer films were fabricated on quartz substrates by radio frequency (RF) sputtering using SnO2 and Al targets. The deposited films were annealed at a fix temperature of 500 °C for different time durations (1–8 h). The effect of annealing time on the structural, morphological, optical and electrical performances of SnO2/Al/SnO2 multilayer films was studied. X-ray diffraction (XRD) results show that all the p-type conducting films possess polycrystalline SnO2 with tetragonal rutile structure. Hall-effect results indicate that 500 °C for 1 h is the optimum annealing condition for p-type SnO2/Al/SnO2 multilayer films, resulting in a hole concentration of 1.14×1018 cm–3 and a low resistivity of 1.38 Ω·cm, respectively. The optical transmittance of the p-type SnO2/Al/SnO2 multilayer films is above 80% within annealing time range of 1–8 h, showing maximum for the films annealed for 1 h. 相似文献
6.
R. Mechiakh N. Ben Sedrine J. Ben Naceur R. Chtourou 《Surface & coatings technology》2011,205(2-3):243-249
Nanocrystalline TiO2 thin films were deposited on a ITO coated glass substrate by sol–gel dip coating technique, the layers undergo a heat treatment at temperatures varying from 300 to 450 °C. The structural, morphological and optical characterizations of the as deposited and annealed films were carried out using X-ray diffraction (XRD), Raman spectroscopy, Atomic Force Microscopy (AFM), visible, (Fourier-Transform) infrared and ultraviolet spectroscopy, Fluorescence and spectroscopic ellipsometry. The results indicate that an anatase phase structure TiO2 thin film with nanocrystallite size of about 15 nm can be obtained at the heat treatment temperature of 350 °C or above, that is to say, at the heat treatment temperature below 300 °C, the thin films grow in amorphous phase; while the heat treatment temperature is increased up to 400 °C or above, the thin film develops a crystalline phase corresponding to the titanium oxide anatase phase. We have accurately determined the layer thickness, refractive index and extinction coefficient of the TiO2 thin films by the ellipsometric analysis. The optical gap decreases from 3.9 to 3.5 eV when the annealing temperature increases. Photocatalytic activity of the TiO2 films was studied by monitoring the degradation of aqueous methylene blue under UV light irradiation and was observed that films annealed above 350 °C had good photocatalytic activity which is explained as due to the structural and morphological properties of the films. 相似文献
7.
Ferroelectric properties of dysprosium-doped Bi4Ti3O12 thin films crystallized in various atmospheres 总被引:1,自引:0,他引:1
Dysprosium-doped Bi4Ti3O12 (Bi3.4Dy0.6Ti3O12, BDT) ferroelectric thin films were deposited on Pt(111)/Ti/SiO2/Si(111) substrates by chemical solution deposition (CSD) and crystallized in nitrogen, air and oxygen atmospheres, respectively. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to identify the crystal structure, the surface and cross-section morphology of the deposited ferroelectric films. The results show that the crystallization atmosphere has significant effect on determining the crystallization and ferroelectric properties of the BDT films. The film crystallized in nitrogen at a relatively low temperature of 650 ℃, exhibits excellent crystallinity and ferroelectricity with a remanent polarization of 2Pr = 24.9 ℃/cm^2 and a coercive field of 144.5 kV/cm. While the films annealed in air and oxygen at 650 ℃ do not show good crystallinity and ferroelectricity until they are annealed at 700 ℃. The structure evolution and ferroelectric properties of BDT thin films annealed under different temperatures (600-750 ℃) were also investigated. The crystallinity of the BDT films is improved and the average grain size increases when the annealing temperature increases from 600 ℃ to 750 ℃ at an interval of 50 ℃. However, the polarization of the films is not monotonous function of the annealing temperature. 相似文献
8.
《中国有色金属学会会刊》2006,16(3):545-550
Cathode material LiMn2O4 thin films were prepared through solution deposition followed by rapid thermal annealing. The phase identification and surface morphology were studied by X-ray diffraction and scanning electron microscopy. Electrical and electrochemical properties were examined by four-probe method, cyclic voltammetry and galvanostatic charge-discharge experiments. The results show that the film prepared by this method is homogeneous, dense and crack-free. As the annealing temperature and annealing time increase, the electronic resistivity decreases, while the capacity of the films increases generally. For the thin films annealed at different temperatures for 2 min, the thin film annealed at 800 °C has the best cycling behavior with the capacity loss of 0.021% per cycle. While for the thin films annealed at 750 °C for different times, the film annealed for 4 min possesses the best cycling performance with a capacity loss of 0.025% per cycle. For the lithium diffusion coefficient in LiMn2O4 thin film, its magnitude order is 10−11 cm2·s−1. 相似文献
9.
Ju-Won JeonDae-Woo Jeon Trilochan SahooMyoung Kim Jong-Hyeob BaekJessica Lynn Hoffman Nam Soo KimIn-Hwan Lee 《Journal of Alloys and Compounds》2011,509(41):10062-10065
The effect of annealing temperature on the electrical and optical properties of indium zinc oxide (IZO) (In2O3:ZnO = 90:10 wt.%) thin films has been investigated. The IZO thin films were deposited on glass substrates by radio frequency magnetron sputtering and then subjected to annealing in a mixed ambient of air and oxygen at 100, 200 and 300 °C. All the IZO films were found to have amorphous structure. With the increase of the annealing temperature, the carrier concentration decreased and the resistivity increased. The average transmittance of IZO thin films decreased slightly with annealing temperature. Interestingly, a systematic reduction of the optical band-gap from 3.79 eV to 3.67 eV was observed with annealing temperature. The change in optical band-gap was observed to be caused predominantly by Burstein-Moss band-gap widening effect suggesting unusual absence of band narrowing effect. The effects on optical and electrical properties of IZO films have been discussed in detail. 相似文献
10.
Noncrystalline VOx thin films were deposited onto p-doped Si (100) substrates at 400 °C using magnetron sputtering. By vacuum annealing, we obtained polycrystalline VO2 thin films with two different structures under a variety of annealing conditions. With the annealing temperature increasing and the annealing time developing, structures of the films underwent the following transformation: amorphous structure→metastable VO2 (B)→VO2 (B) + VO2 (M). Vacuum annealing is useful of acquiring VO2 thin films with high surface quality, but too high annealing temperature (500 °C) and too long time (15 h) are harmful, which make the surface degenerate. 相似文献
11.
Highly transparent, p-type conducting SnO2:Zn thin films are prepared from the thermal diffusion of a sandwich structure of Zn/SnO2/Zn multilayer thin films deposited on quartz glass substrate by direct current (DC) and radio frequency (RF) magnetron sputtering using Zn and SnO2 targets. The deposited films were annealed at various temperatures for thermal diffusion. The effect of annealing temperature and time on the structural, electrical and optical performances of SnO2:Zn films was studied. XRD results show that all p-type conducting films possessed polycrystalline SnO2 with tetragonal rutile structure. Hall effect results indicate that the treatment at 400 °C for 6 h was the optimum annealing parameters for p-type SnO2:Zn films which have relatively high hole concentration and low resistivity of 2.389 × 1017 cm− 3 and 7.436 Ω cm, respectively. The average transmission of the p-type SnO2:Zn films was above 80% in the visible light range. 相似文献
12.
Hafnium oxide (HfO2) thin films were grown on silicon and quartz substrates by radio frequency reactive magnetron sputtering at temperature < 52 °C. X-ray diffraction of the films showed no structure, suggesting that the films grown on the substrates are amorphous. The optical properties of these films have been investigated using spectroscopic ellipsometry with wavelength range 200-1400 nm and ultraviolet-visible spectrophotometer techniques. Also, the effects of annealing temperatures on the structure and optical properties of the amorphous HfO2 (a-HfO2) have been investigated. The films appeared to be monoclinic structure upon high temperature (1000 °C) annealing as confirmed by X-ray diffraction. The results show that the annealing temperature has a strong effect on the optical properties of a-HfO2 films. The optical bandgap energy of the as-deposited films is found to be about 5.8 eV and it increases to 5.99 eV after the annealing in Ar gas at 1000 °C. The further study shows that the measurement of the optical properties of the amorphous films reveals a high transmissivity (82%-99%) and very low reflectivity (< 8%) in the visible and near-infrared regions at any angle of incidence. Thus, the amorphous structure yields HfO2 film of significantly higher transparency than the polycrystalline (68%-83%) and monoclinic (78%-89%) structures. This means that the a-HfO2 films could be a good candidate for antireflection (AR) optical coatings. 相似文献
13.
《Acta Materialia》2001,49(1):83-92
Phase transformation and defect structures in thin-film TiSi2 produced by co-sputtering have been investigated as a function of annealing temperature by transmission electron microscopy. Metastable C49 crystallites nucleate first in the amorphous matrix from as low as 100°C. This is due to the lower surface energy of C49 crystallites arising from the similarity in electronic structure, chemical bonding and atomic density between the C49 and amorphous modifications. All C49 crystallites contain numerous (010) faults, which are boundaries between two differently oriented domains related to each other by a 90° rotation about [010]. Stable C54 crystallites nucleate in the C49 matrix above 700°C and most C54 crystallites contain twins with the twin habit plane parallel to (001), which is perpendicular to the {110} twinning plane. Ternary additions to TiSi2 thin films to reduce the C49→C54 transformation temperature are discussed on the basis of the results from electron energy-loss spectroscopy (EELS) analyses described in the companion paper. 相似文献
14.
Effects of annealing temperature and time on microstructure and magnetic properties of Pr-Co thin films 总被引:1,自引:1,他引:0
A series of Pr-Co thin films were deposited on the Si (100) substrates with Cr underlayer by magnetron sputtering. The effects of both the post-annealing temperature and the annealing time on the microstructure and magnetic properties for the Pr-Co films were studied systemati- cally. The as-deposited Pr-Co thin films are mostly amorphous and tend to crystallize after annealing at temperatures above 600 C. When the annealing time is increased, the films show a complicated structure with various phases coexisting. Accordingly, the as-deposited film and low temperature annealed films are soft magnets and films annealed at temperatures beyond 600 C tend to be hard magnets. When the annealing time is increased from 5 min to 2 h, the films transfer from hard magnets to soft again. The sample annealed at 600 C for 10 min shows the largest coercivity of 0.59 T. 相似文献
15.
Zirconium oxide thin films were deposited using pulsed laser ablation from a ceramic ZrO2 target on unheated substrates. Subsequently, the films were annealed in air in the temperature range 400-800 °C. The films were characterized by X-ray diffraction, atomic force microscopy, X-ray photoelectron spectroscopy, and optical spectroscopy to investigate the variation of the structural, chemical, and optical properties upon annealing. As-deposited films were amorphous and had a large surface density of ablated particles. Annealing resulted in the growth of monoclinic nano-crystalline, uniform, and transparent films that were slightly sub-stoichiometric. The annealed films were compact and had high values of the refractive index. Extinction coefficients were small, and may be related to the presence of defects. The films exhibited the presence of an indirect band gap, related to defects, and a direct band gap, related to fundamental absorption. 相似文献
16.
Yinzhi Chen Hongchuan Jiang Shuwen Jiang Xingzhao Liu Wanli Zhang Qinyong Zhang 《金属学报(英文版)》2014,27(2):368-372
Indium tin oxide(ITO) thin films were prepared on alumina ceramic substrates by radio frequency magnetron sputtering.The samples were subsequently annealed in air at temperatures ranging from 500 to 1,100 °C for 1 h.The influences of the annealing temperature on the microstructure and electrical properties of the ITO thin films were investigated,and the results indicate that the as-deposited ITO thin films are amorphous in nature.All samples were crystallized by annealing at 500 °C.As the annealing temperature increases,the predominant orientation shifts from(222)to(400).The carrier concentration decreases initially and then increases when the annealing temperature rises beyond1,000 °C.The resistivity of the ITO thin films increases smoothly as the annealing temperature increases to just below900 °C.Beyond 900 °C,however,the resistivity of the films increases sharply.The annealing temperature has a significant effect on the stability of the ITO/Pt thin film thermocouples(TFTCs).TFTCs annealed at 1,000 °C show improved hightemperature stability and Seebeck coefficients of up to 77.73 μV/°C. 相似文献
17.
《Synthetic Metals》1999,99(1):45-52
In this paper a review of recent progress achieved in the domain of MX2 films (M=Mo, W; X=Se, S) is presented. The MoS2 is essentially discussed. It is shown that the emerging interest in the use of MX2 thin films as absorbing layer in photovoltaic cells has induced significant improvements of the crystalline and optoelectrical properties of these films. Some years ago the films obtained were crystallized in the 2H-MoS2 structure but the size of their crystallites was small and the samples were poorly photoconductive. Recently many works have shown that, whatever the deposition technique used, textured films with large grains and good photoconductive properties could be obtained when a thin nickel layer is used. During the post annealing treatment, this thin nickel layer diffuses all over the thickness of the films. It is proposed that systematically the crystallization process of MX2 films is a two-step process. The primary crystallization corresponds to small crystallites formation and the secondary crystallization corresponds to large ordered domains growth by coalescence of the small crystallized domains. This secondary crystallization process is facilitated by the presence of Van der Waals surfaces parallel to the plane of the substrate. Moreover, this effect is strongly improved in the presence of nickel which allows the obtention of high quality films. The electrical properties of these films are interpreted with the help of grain boundary theories. 相似文献
18.
D. Beena K.J. Lethy R. Vinodkumar A.P. Detty V.P. Mahadevan Pillai V. Ganesan 《Journal of Alloys and Compounds》2010,489(1):215-223
Nanocrystalline indium oxide films have been deposited using pulsed laser ablation technique at different substrate temperatures and the films are post-annealed at different temperatures. The structural, optical and electrical properties of the films are investigated by XRD, SEM, AFM, UV–vis spectra, photoluminescence spectra and electrical conductivity measurements. X-ray diffractograms of the as-deposited and post-annealed films A–C show that films are amorphous at lower substrate temperatures and transform to mixture of amorphous and crystalline phases. The grain size determination based on Debye Scherrer's formula shows that the average grain size of the crystallites in the films ranges from 6 to 32 nm. Dislocation density, biaxial strain, lattice strain and lattice stress of the films are also calculated. SEM micrographs show that all the films are densely packed with the crystallites in the nanodimensions. SEM images show porous nanocrystalline nature for the films of samples B and C which make them suitable for gas sensing. The as-deposited samples show decrease in resistivity with increase in substrate temperature and the lowest resistivity obtained is 6.6 × 10?5 Ω m for the as-deposited films at substrate temperature 773 K. Efficient photoluminescence emission is observed in all the films and this can be attributed to higher values of rms surface roughness exhibited by these films. In2O3 films exhibit a PL emission property in the UV region at room temperature which suggests possible applications in nanoscale optoelectronic devices in the future. 相似文献
19.
S.N. Karthick S. Richard Prabhu Gnanakan A. Subramania Hee-Je Kim 《Journal of Alloys and Compounds》2010,489(2):674-677
Nanocrystalline cubic spinel lithium manganese oxide thin film was prepared by a polymer spray pyrolysis method using lithium acetate and manganese acetate precursor solution and polyethylene glycol-4000 as a polymeric binder. The substrate temperature was selected from the thermogravimetric analysis by finding the complete crystallization temperature of LiMn2O4 precursor sample. The deposited LiMn2O4 thin films were annealed at 450, 500 and 600 °C for 30 min. The thin film annealed at 600 °C was found to be the sufficient temperature to form high phase pure nanocrystalline LiMn2O4 thin film. The formation of cubic spinel thin film was confirmed by X-ray diffraction study. Scanning electron microscopy and atomic force microscopy analysis revealed that the thin film annealed at 600 °C was found to be nanocrystalline in nature and the surface of the films were uniform without any crack. The electrochemical charge/discharge studies of the prepared LiMn2O4 film was found to be better compared to the conventional spray pyrolysed thin film material. 相似文献
20.
H. Mahfoz Kotb M.A. DabbanA.Y. Abdel-latif M.M. Hafiz 《Journal of Alloys and Compounds》2012,512(1):115-120
Structural and optical properties of selenium-rich CdSe (SR-CdSe) thin films prepared by thermal evaporation are studied as a function of annealing temperature. X-ray diffraction (XRD) patterns show that the as-prepared films were amorphous, whereas the annealed films are polycrystalline. Analyzing XRD patterns of the annealed films reveal the coexistence of both (hexagonal) Se and (hexagonal) CdSe crystalline phases. Surface roughness of SR-CdSe films is measured using atomic force microscope (AFM). Analyses of the absorption spectra in the wavelength range (200-2500 nm) of SR-CdSe thin films indicates the existence of direct and indirect optical transition mechanisms. The optical band gap (Eg) of as-prepared film is 1.92 and 2.14 eV for the indirect allowed and direct allowed transitions respectively. After annealing, the absorption coefficient and optical band gap were found to decrease, while the values of refractive index (n) and the extinction coefficient (kex) increase. The dispersion of the refractive index is described using the Wimple-Di Domenico (WDD) single oscillator model and the dispersion parameters are calculated as a function of annealing temperature. Besides, the high frequency dielectric constant (?∞) and the ratios of the free carrier concentration to its effective mass (N/m*) are studied as a function of annealing temperature. The results are discussed and correlated in terms of amorphous-crystalline transformations. 相似文献