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1.
Electrical and optical properties of polycrystalline films of W-doped indium oxide (IWO) were investigated. These films were deposited on glass substrate at 300 °C by d.c. magnetron sputtering using ceramic targets. The W-doping in the sputter-deposited indium oxide film effectively increased the carrier density and the mobility and decreased the resistivity. A minimum resistivity of 1.8 × 10− 4 Ω cm was obtained at 3.3 at.% W-doping using the In2O3 ceramic targets containing 7.0 wt.% WO3. The 2.2 at.% W-doped films obtained from the targets containing 5.0 wt.% WO3, showed the high Hall mobility of 73 cm2 V− 1 s− 1 and relatively low carrier density of 2.9 × 1020 cm− 3. Such properties resulted in novel characteristics of both low resistivity (3.0 × 10− 4 Ω cm) and high transmittance in the near-infrared region. 相似文献
2.
Optical and electrical properties were studied on thin polycrystalline ZnO films (200-nm thick) deposited on glass substrates at 200 °C by a DC-arc ion plating method (URamoto-Tanaka-type ion plating method). Effects of the oxygen flow rate (OFR) on film properties were examined. The resistivity of undoped films changed from 4.2×10−3 to 9.6×10−1 Ω cm, corresponding to the carrier concentration of 1.0×1020-1.2×1018 cm−3, depending on the increase in OFR from 0 to 40 sccm. The Hall mobility tends to be the maximum value of 28 cm2 (V s)−1 at OFR of 10 sccm. Photoluminescence (PL) spectra exhibited a dominant near-band-edge (NBE) emission together with weak PL bands at 2.2 and 3.2 eV. Intensity of NBE was maximum at OFR of 10 sccm. Intensity of the PL band at 2.2 eV increased with increase in OFR. As a result of Ga-doping, the resistivity decreased and the carrier concentration increased by one order of magnitude. The optical transmittance was more than 90% in 400-1200 nm. The ZnO:Ga (3 and 4 wt.% Ga-doped) thin films with the lowest resistivity of 2.6×10−4 Ω cm, the highest mobility of 25 cm2 (V s)−1, and the highest PL intensity were obtained at OFR of 10 sccm. Further increase of OFR led to the decrease in both mobility and PL intensity. 相似文献
3.
S. Kaleemulla 《Materials Letters》2007,61(21):4309-4313
Indium oxide (In2O3) thin films were prepared by flash evaporated technique under various substrate temperatures in the range of 303-673 K and systematically studied the structural, electrical and optical properties of the deposited films. The films formed at substrate temperatures of < 373 K were amorphous while those deposited at higher substrate temperatures (≥ 373 K) were polycrystalline in nature. The optical band gap of the films decreased from 3.71 eV to 2.86 eV with the increase of substrate temperature from 303 K to 673 K. Figure of merit of the films increased from 2.8 × 103 Ω− 1 cm− 1 to 4.2 × 103 Ω− 1 cm− 1 with increasing substrate temperature from 303 K to 573 K, thereafter decreased to 2.2 × 103 Ω− 1 cm− 1 at higher temperature of 673 K. 相似文献
4.
Structural, electrical and optical properties of zirconium-doped zinc oxide films prepared by radio frequency magnetron sputtering 总被引:1,自引:0,他引:1
Transparent and conducting zirconium-doped zinc oxide films have been prepared by radio frequency magnetron sputtering at room temperature. The ZrO2 content in the target is varied from 0 to 10 wt.%. The films are polycrystalline with a hexagonal structure and a preferred orientation along the c axis. As the ZrO2 content increases, the crystallinity and conductivity of the film are initially improved and then both show deterioration. Zr atoms mainly substitute Zn atoms when the ZrO2 content are 3 and 5 wt.%, but tend to cluster into grain boundaries at higher contents. The lowest resistivity achieved is 2.07 × 10− 3 Ω cm with the ZrO2 content of 5 wt.% with a Hall mobility of 16 cm2 V− 1 s− 1 and a carrier concentration of 1.95 × 1020 cm− 3. All the films present a high transmittance of above 90% in the visible range. The optical band gap depends on the carrier concentration, and the value is larger at higher carrier concentration. 相似文献
5.
Valence electron control and electron transport mechanisms on the amorphous indium zinc oxide (IZO) films were investigated. The amorphous IZO films were deposited by dc magnetron sputtering using an oxide ceramic IZO target (89.3 wt.% In2O3 and 10.7 wt.% ZnO). N-type impurity dopings, such as Sn, Al or F, could not lead to the increase in carrier density in the IZO. Whereas, H2 introduction into the IZO deposition process was confirmed to be effective to increase carrier density. By 30% H2 introduction into the deposition process, carrier density increased from 3.08 × 1020 to 7.65 × 1020 cm− 3, which must be originated in generations of oxygen vacancies or interstitial Zn2+ ions. Decrease in the transmittance in the near infrared region and increase in the optical band gap were observed with the H2 introduction, which corresponded to the increase in carrier density. The lowest resistivity of 3.39 × 10− 4 Ω cm was obtained by 10% H2 introduction without substrate heating during the deposition. 相似文献
6.
A. Moses Ezhil Raj V. Agnes C. Ravidhas M. Suendorf M. Jayachandran 《Thin solid films》2010,519(1):129-135
Anatase phase titanium dioxide thin films have been deposited at various substrate temperatures by chemical spray pyrolysis of an aerosol of titanyl acetylacetonate. Deposited TiO2 films were nanocrystalline and preferentially oriented along [101] direction, uniform and adherent to the glass substrate. Best films processed at 450 °C were characterized to analyze its phase composition, texture, roughness, optical and electrical properties. X-ray photoelectron spectroscopy revealed that the surface of the film has only the Ti4+ cations to form perfect TiO2 stoichiometry with less amount of hydration. Atomic force microscopy image demonstrated the existence of homogeneous and rough surface, suitable for electrocatalytic applications. The film has an optical transmittance more than 90% and the refractive index of 2.07 was recorded at the wavelength 633 nm. Due to nano-sized grains, obtained optical band gap (3.65 eV) of the TiO2 thin film was larger than that of the bulk TiO2 (3.2 eV). Calculated porosity of the films 0.44, revealed the porous nature of the films. Hall measurements indicated that these materials are p-type and yield a carrier density of the order 8.8 × 1020 cm−3 and a carrier mobility of 0.48 × 10−6 cm2/Vs. The dc electrical conductivity was therefore very low (8.91 × 10−6 S/cm) because of lower value of mean free path of the charge carriers (4.36 × 10−11 cm). It gives an impression that the process of spray pyrolysis provides an easy way to tailor make thin films possessing superior properties. 相似文献
7.
Al-doped zinc oxide (AZO) thin films were deposited onto flexible polyethylene terephthalate substrates, using the radio frequency (RF) magnetron sputtering process, with an AZO ceramic target (The Al2O3 content was about 2 wt.%). The effects of the argon sputtering pressure (in the range from 0.66 to 2.0 Pa), thickness of the Al buffer layer (thickness of 2, 5, and 10 nm) and annealing in a vacuum (6.6 × 10− 4 Pa), for 30 min at 120 °C, on the morphology and optoelectronic performances of AZO films were investigated. The resistivity was 9.22 × 10− 3 Ω cm, carrier concentration was 4.64 × 1021 cm− 3, Hall mobility was 2.68 cm2/V s and visible range transmittance was about 80%, at an argon sputtering pressure of 2.0 Pa and an RF power of 100 W. Using an Al buffer decreases the resistivity and optical transmittance of the AZO films. The crystalline and microstructure characteristics of the AZO films are improved by annealing. 相似文献
8.
In this study, CuFeO2 thin films were deposited onto quartz substrates using a sol-gel and a two-step annealing process. The sol-gel-derived films were annealed at 500 °C for 1 h in air and then annealed at 600 to 800 °C for 2 h in N2. X-ray diffraction patterns showed that the annealed sol-gel-derived films were CuO and CuFe2O4 phases in air annealing. When the films were annealed at 600 °C in N2, an additional CuFeO2 phase was detected. As the annealing temperature increased above 650 °C in N2, a single CuFeO2 phase was obtained. The binding energies of Cu-2p3/2, Fe-2p3/2, and O-1s were 932.5 ± 0.1 eV, 710.3 ± 0.2 eV and 530.0 ± 0.1 eV for CuFeO2 thin films. The chemical composition of CuFeO2 thin films was close to its stoichiometry, which was determined by X-ray photoelectron spectroscopy. Thermodynamic calculations can explain the formation of the CuFeO2 phase in this study. The optical bandgap of the CuFeO2 thin films was 3.05 eV, which is invariant with the annealing temperature in N2. The p-type characteristics of CuFeO2 thin films were confirmed by positive Hall coefficients and Seebeck coefficients. The electrical conductivities of CuFeO2 thin films were 0.28 S cm− 1 and 0.36 S cm− 1 during annealing at 650 °C and 700 °C, respectively, in N2. The corresponding carrier concentrations were 1.2 × 1018 cm− 3 (650 °C) and 5.3 × 1018 cm− 3 (700 °C). The activation energies for hole conduction were 140 meV (650 °C) and 110 meV (700 °C). These results demonstrate that sol-gel processing is a feasible preparation method for delafossite CuFeO2 thin films. 相似文献
9.
Bo Hyun Kong 《Thin solid films》2010,518(11):2975-2979
We investigated the structural, electrical, and optical properties of ZnO thin films grown at different VI/II ratios on sapphire substrates by metalorganic chemical vapor deposition. Transmission electron microscopy and X-ray diffraction revealed the epitaxial nature with a reduced dislocation density of the ZnO films grown at increased VI/II ratios. The carrier concentration of the films increased to 4.9 × 1018 cm− 3 and their resistivity decreased to 1.4 × 10− 1 Ω cm at a VI/II ratio of 513.4 μmol/min. The ZnO films also showed good optical transmittance (> 80%) in the visible and near-infrared wavelength regions. The room temperature PL revealed a strong band-edge emission with a weak deep level emission, suggesting the good crystalline quality of the ZnO films on the sapphire substrates. Furthermore, the intensity ratio of the band-edge emission to the deep-level emission (IUV/IVis) increased with increasing VI/II ratio. 相似文献
10.
Zinc oxide transparent conducting thin films co-doped with aluminum and ruthenium were grown on polyethylene terephthalate substrates at room temperature using RF magnetron sputtering. The crystal growth and physical properties of the films were investigated with respect to the variation of discharge power density from 1.5 to 6.1 W/cm2 and sputtering pressure from 0.13 to 2.0 Pa. X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) showed that the films grown with 3.6 W/cm2 power density and sputtering pressure of 0.4 Pa had the best crystallinity and larger pyramid-like grains. The optimized electrical resistivity had a lowest measured value of about 9 × 10−4 Ω cm. The low carrier mobilities of the films (3-8.9 cm2 V−1 s−1) have been discussed in terms of what is believed to be the dominant effect of ionized impurity scattering, but in addition chemisorption of oxygen on the film surface and effect of grain boundaries are also thought to be significant. The transmittances of the films in the visible range are greater than 80%, while the optical band gaps are in the order of 3.337-3.382 eV. 相似文献
11.
Fumiaki Mitsugi Yoshihiro Umeda Norihiro Sakai Tomoaki Ikegami 《Thin solid films》2010,518(22):6334-1307
Recently, transparent conducting oxide thin films have attracted attention for the application to transparent conducting electrodes. In this work, we evaluated the uniformity of electrical, optical and structural properties for gallium doped zinc oxide thin films prepared on the 10 × 10 cm2 silica glass substrate by pulsed laser deposition. The resistivity, carrier concentration, mobility, bonding state and atomic composition of the film were uniform along in-plane and depth direction over the 10 × 10 cm2 area of the substrate. The film showed the average transmittance of 81-87%, resistivity of 1.4 × 10− 3 Ω cm, carrier concentration of 9.7 × 1020/cm3 and mobility of 5 cm2/Vs in spite of the amorphous X-ray diffraction pattern. The gradual thickness distribution was found, however, the potential for large-area and low temperature deposition of transparent conducting oxide thin film using pulsed laser deposition method was confirmed. 相似文献
12.
David H. O’Neil Vladimir L. Kuznetsov Robert. M.J. Jacobs Martin O. Jones Peter P. Edwards 《Materials Chemistry and Physics》2010
Highly conducting (σ ∼ 2.6 × 103 Ω−1 cm−1) In4Sn3O12 films have been deposited using pulsed laser deposition (PLD) on glass and quartz substrates held at temperatures between 350 and 550 °C under chamber pressures of between 2.5 and 15 mTorr O2. The crystallinity and the surface roughness of the films were found to increase with increasing substrate temperature. Electron concentrations of the order of 5 × 1020 cm−3 and mobilities as high as 30 cm2 V−1 s−1 were determined from Hall effect measurements performed on the films. Fitting of the transmission spectral profiles in the ultra-violet–visible spectrum has allowed the determination of the refractive index and extinction coefficient for the films. A red-shift in the frequency of plasmon resonance is observed with both increasing substrate temperature and oxygen pressure. Effective masses have been derived from the plasma frequencies and have been found to increase with carrier concentration indicating a non-parabolic conduction band in the material In4Sn3O12. The optical band-gap has been determined as 3.8 eV from the analysis of the absorption edge in the UV. These results highlight the potential of these films as lower In-content functional transparent conducting materials. 相似文献
13.
Excess oxygen and 1-at% Mg co-doped CuScO2[3R](0001) epitaxial films were prepared on a-plane sapphire substrates by combining two-step deposition and post-annealing techniques. The optical and electrical transport properties of the co-doped epitaxial films were compared with those of the CuScO2[3R](0001) epitaxial films. No significant increase in optical absorption was observed in the co-doped epitaxial films, and the energy gap for direct allowed transition was estimated at 3.7 eV. The carrier concentration of CuScO2[3R](0001) epitaxial films was controlled from ~ 1016 cm- 3 to ~ 1018 cm- 3 at room temperature by adjusting the excess oxygen and Mg co-doping. The electrical conductivity, carrier concentration, and Hall mobility of the most conductive film were 3.6 × 10- 2 Scm- 1, 8.5 × 1017 cm- 3 and 2.6 × 10- 1 cm2V- 1 s- 1 at room temperature, respectively. The temperature dependence of the electrical transport properties of the film exhibited semiconducting characteristics, and the activation energy estimated from the temperature dependence of the carrier concentration was 0.50 eV. 相似文献
14.
Transparent diode heterojunction on ITO coated glass substrates was fabricated using p-type AgCoO2 and n-type ZnO films by pulsed laser deposition (PLD). The PLD of AgCoO2 thin films was carried out using the pelletized sintered target of AgCoO2 powder, which was synthesized in-house by the hydrothermal process. The band gap of these thin films was found to be ∼ 3.89 eV and they had transmission of ∼ 55% in the visible spectral region. Although Hall measurements could only indicate mixed carrier type conduction but thermoelectric power measurements of Seebeck coefficient confirmed the p-type conductivity of the grown AgCoO2 films. The PLD grown ZnO films showed a band gap of ∼ 3.28 eV, an average optical transmission of ∼ 85% and n-type carrier density of ∼ 4.6 × 1019 cm− 3. The junction between p-AgCoO2 and n-ZnO was found to be rectifying. The ratio of forward current to the reverse current was about 7 at 1.5 V. The diode ideality factor was much greater than 2. 相似文献
15.
Indium molybdenum oxide thin films were RF sputtered at room temperature on glass substrates with a reference base pressure of 7.5 × 10− 4 Pa. The electrical and optical properties of the films were studied as a function of oxygen partial pressures (OPP) ranging from 1.5 × 10− 3 Pa to 3.5 × 10− 3 Pa. The obtained data show that the bulk resistivity of the films increased by about 4 orders of magnitude (from 7.9 × 10− 3 to 7.6 × 101 Ω-cm) when the OPP increased from 1.5 × 10−3 to 3.5 × 10− 3 Pa, and the carrier concentration decreased by about 4 orders (from 1.77 × 1020 to 2.31 × 1016 cm− 3). On the other hand, the average visible transmittance of 30.54% of the films (brown colour; OPP = 1.5 × 10− 3 Pa) was increased with increasing OPP to a maximum of 80.47% (OPP = 3.5 × 10− 3 Pa). The optical band gap calculated from the absorption edge of the transmittance spectra ranges from 3.77 to 3.88 eV. Further, the optical and electrical properties of the films differ from those deposited at similar conditions but with a base pressure lower than 7.5 × 10− 4 Pa. 相似文献
16.
Akihiko Kono 《Vacuum》2009,84(5):625-628
A hot-cathode plasma sputtering technique was used for fabricating the highly transparent and conducting aluminum-doped zinc oxide (AZO) films on glass substrates from a disk-shaped AZO (Al2O3: 2 wt.%) target. Under particular conditions where the target voltage was VT = −200 V and the plasma excitation pressure was PS = 1.5 × 10−3 Torr, the lowest resistivity of 4.2 × 10−4 Ω cm was obtained at 400 nm, and this was associated with a carrier density of 8.7 × 1020 cm−3 and a Hall mobility of 17 cm2/V s. From the annealing experiment of the AZO films in the oxygen and nitrogen gases of the atmospheric pressure it was revealed that both the oxygen vacancies and the grain boundaries in the polycrystalline AZO film played an important role in the electrical properties of the film. 相似文献
17.
Thin films of indium doped cadmium oxide were deposited on quartz substrate using pulsed laser deposition technique. The effect of growth temperature and partial oxygen pressure on structural, optical and electrical properties was studied. We find that the optical transparency of the films largely depends on the growth temperature, while partial oxygen pressure has virtually no effect on the transparency of the films. Electrical properties are found to be sensitive to both the growth temperature and oxygen pressure. It is observed that conductivity and carrier concentration decreases with temperature. The film grown at 200 °C under an oxygen pressure of 5.0 × 10− 4 mbar shows high mobility (155 cm2/V s), high carrier concentration (1.41 × 1021 cm3), and low resistivity (2.86 × 10− 5 Ω cm). 相似文献
18.
Transparent conducting Al and Y codoped zinc oxide (AZOY) thin films with high transparency and low resistivity were deposited by DC magnetron sputtering. The effects of substrate temperature on the structural, electrical and optical properties of AZOY thin films deposited on glass substrates have been investigated. X-ray diffraction spectra indicate that no diffraction peak of Al2O3 or Y2O3 except that of ZnO (0 0 2) is observed. The AZOY thin film prepared at substrate temperature of 250 °C has the optimal crystal quality inferring from FWHM of ZnO (0 0 2) diffraction peak, but the AZOY thin film deposited at 300 °C has the lowest resistivity of 3.6 × 10−4 Ω-cm, the highest mobility of 30.7 cm2 V−1 s−1 and the highest carrier concentration of 5.6 × 1020 cm−3. The films obtained have disorderly polyhedral surface morphology indicating possible application in thin film solar cell with good quality and high haze factor without the need of post-deposition etching. 相似文献
19.
Fluorine-doped tin oxide (FTO) films were prepared at different substrate temperatures by ultrasonic spray pyrolysis technique on glass substrates. Among F-doped tin oxide films, the lowest resistivitiy was found to be 6.2 × 10− 4 Ω-cm for a doping percentage of 50 mol% of fluorine in 0.5 M solution, deposited at 400 °C. Hall coefficient analyses and secondary ion mass spectrometry (SIMS) measured the electron carrier concentration that varies from 3.52 × 1020 cm− 3 to 6.21 × 1020 cm− 3 with increasing fluorine content from 4.6 × 1020 cm− 3 to 7.2 × 1020 cm− 3 in FTO films deposited on various temperatures. Deposition temperature on FTO films has been optimized for achieving a minimum resistivity and maximum optical transmittance. 相似文献
20.
ZnS films were deposited by spray pyrolysis on glass at 500 °C substrate temperature. In order to study the influence of fluorine on the properties of ZnS film, undoped and F-doped films were investigated using X-ray diffraction, scanning electron microscopy and optical transmittance spectroscopy. The absorption coefficient was measured and correlated with the photon energy to estimate the energy gap, which rises from 3.20 to 3.35 eV with increased F content. Carrier concentrations of our samples were determined from Hall effect measurements. It was found that the carrier concentration increases from 7.0 × 1012 cm− 3 to 8.0 × 1013 cm− 3 with increasing F content from 0 to 6 wt.% in ZnS films. 相似文献