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1.
《Current Applied Physics》2007,7(1):51-59
Electrochromic molybdenum oxide (MoO3) thin films were prepared by electron beam evaporation technique using the dry MoO3 pellets. The films were deposited on glass and fluorine doped tin oxide (SnO2:F or FTO) coated glass substrates at different substrate temperatures like room temperature (RT, 30 °C), 100 °C and 200 °C. The influence of substrate temperature on the structural, surface morphological and optical properties of the films has been studied. The X-ray diffraction analysis showed that the films are having orthorhombic phase MoO3 (α-MoO3) with 〈1 1 0〉 preferred orientation. The laser Raman scattering spectrum shows the polycrystalline nature of MoO3 films deposited at 200 °C. The Raman-active band at 993 cm−1 is corresponding to Mo–O stretching mode that is associated with the unique character of the layered structure of orthorhombic MoO3. Needle—like morphology was observed from the SEM analysis. The energy band gap of MoO3 films was evaluated which lies between 2.8 and 2.3 eV depending on the substrate temperature and substrates. The decrease in band gap value with increasing substrate temperature is owing to the oxygen-ion vacancies. The absorption edge shift shows the coloration effect on the films. 相似文献
2.
Surasing Chaiyakun Artorn Pokaipisit Pichet Limsuwan Boonlaer Ngotawornchai 《Applied Physics A: Materials Science & Processing》2009,95(2):579-587
Titanium dioxide thin films were deposited on three different unheated substrates by unbalanced magnetron sputtering. The
effects of the sputtering current and deposition time on the crystallization of TiO2 thin films were studied. The TiO2 thin films were deposited at three sputtering current values of 0.50, 0.75, and 1.00 A with different deposition times of 25,
35, and 45 min, respectively. The surface morphology of the films was investigated by atomic force microscopy (AFM). The structure
was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The film thickness was determined
by field emission scanning electron microscopy (FE-SEM), and the optical property was evaluated with spectroscopic ellipsometry.
The results show that polycrystalline anatase films were obtained at a low sputtering current value. The crystallinity of
the anatase phase increases as the sputtering current increases. Furthermore, nanostructured anatase phase TiO2 thin films were obtained for all deposition conditions. The grain size of TiO2 thin films was in the range 10–30 nm. In addition, the grain size increases as the sputtering current and deposition time
increase. 相似文献
3.
Transmission spectra (400–1500 nm) of thermally evaporated amorphous [(As2Se3)90Ge10]95M5 thin films have been analyzed to study the effect of impurities (M = Cd and Pb) on their optical properties. The refractive
index increases with addition of metal impurities. The dispersion of refractive index has been studied using Wemple–DiDomenico
single oscillator model. The optical gap has been estimated using Tauc’s extrapolation and was found to decrease with the
addition of metal impurities from 1.46 to 1.36 eV (Cd) and 1.41 eV (Pb) with an uncertainty of ±0.01 eV. The change in optical
properties with metal impurities has been explained on the basis of density, polarizability and bond energy of the system. 相似文献
4.
Jose Antonio Ayllon Monica Lira-Cantu 《Applied Physics A: Materials Science & Processing》2009,95(1):249-255
The effects of oxygen content in the sputtering gas on the crystallographic and optoelectronic properties of 210 nm-thick
Zr–doped In2O3 (Zr–In2O3) films by rf magnetron sputtering were initially studied. The results of X-ray diffraction show that the Zr–In2O3 films grown on glass substrates exhibit mixed crystallographic orientations. Moreover, the Zr–In2O3 film grown in an Ar atmosphere promotes the appearance of crystallographic orientation of (222). The surface of the Zr–In2O3 film becomes rougher as the oxygen content in the sputtering gas decreases; the current images obtained by conductive atomic
force microscopy reveal that the surfaces of the Zr–In2O3 films exhibit a distribution of coexisting conducting and nonconducting regions, and that the area of the nonconducting surface
increases with the oxygen content in the sputtering gas. The resistivity is minimized to 3.51×10−4 Ω cm when the Zr–In2O3 film is grown in an Ar atmosphere and the average transmittance in the visible light region is ∼85%. The optical band gap
decreases as the oxygen content in the sputtering gas increases. 相似文献
5.
Cd1−x
Mg
x
Te is an attractive II–VI semiconductor alloy candidate for obtaining energy gaps wider than 1.5 eV of CdTe needed for the
top junction absorber layer in a polycrystalline thin-film tandem solar cell. We have shown that these alloy films can easily
be prepared by sputtering, however, the sputtering rate is substantially lower than for CdTe and the attainable cell performance
has been poor, both before and after activation treatments with chlorine-containing vapors. In this work we have applied optical
emission spectroscopy (OES) using selected peaks of ArII, CdII, MgI, TeII and correlated the results with crystallographic
and morphological characteristics of the deposited films. Results were obtained as a function of rf sputter power and sputter
gas pressure. 相似文献
6.
Molybdenum oxide (MoO3) thin films were deposited by electron beam evaporation. The chemical composition, microstructure, optical and electrical properties of MoO3 thin films depend on the annealing temperature and ambient atmosphere. X-ray diffraction (XRD) shows that crystalline MoO3 films can be obtained at various post-annealing temperatures from 200 to 500 °C in N2 and O2. X-ray photoelectron spectroscopy (XPS) results reveal that the O-1s emission peak was shifted slightly toward lower binding energies as the annealing temperature in N2 was increased. The oxygen vacancies and conductivity of MoO3 film increased with the annealing temperature. However, when the MoO3 films were annealed in an atmosphere of O2, the optical transmission, the O/Mo ratio and the photon energy increased with the annealing temperature. The results differ from those for films annealed in a N2 atmosphere. 相似文献
7.
Glasses xLi2O–(50-x)(MoO3)2–50P2O5 with x = 10, 20, 30, and 40 mol% were prepared and their optical and electrical properties were investigated. Analysis of the IR
spectra revealed that the Li+ ions act as a glass modifier that enter the glass network by breaking up other linkages and creating non-bridging oxygens
in the network. The optical absorption edge of the glasses was measured for specimens in the form of thin blown films and
the optical absorption spectra of those were recorded in the range 200–800 nm. From the optical absorption edges studies,
the optical band gap (E
opt) and the Urbach energy (E
e) values have been evaluated by following the available semi-empirical theories. The linear variation of (αhν)1/2 with hν, is taken as evidence of indirect interband transitions. The E
opt values were found to decrease with increasing Li2O content by causing increase in the number of non-bridging oxygens in network. The Urbach tail analysis gives the width of
localized states between 0.48 and 0.74 eV. 相似文献
8.
Cheng-Fu Yang Hong-Hsin Huang Cheng-Yi Chen Ping-Chih Huang Chien-Chen Diao 《Applied Physics A: Materials Science & Processing》2009,94(1):117-122
In this study, two different thin films, TiO2 thin film and TiO2–W–TiO2 multi-layer thin films (W, tungsten), are prepared by RF magnetron sputtering onto glass substrates. The crystal structure,
morphology, and transmittance of TiO2 and TiO2–W–TiO2 multi-layer thin films are investigated by X-ray diffraction, SEM, and UV-Vis spectrometer, respectively. The amorphous,
rutile, and anatase TiO2 phases are observed in the TiO2 thin film and in the TiO2–W–TiO2 multi-layer thin films. The deposition of tungsten as the inter-layer will have large effect on the transmittance and phase
ratios of rutile and anatase phases in the TiO2–W–TiO2 multi-layer thin films. The crystal intensities of amorous TiO2 will decrease as the tungsten is used as the middle layer in the multi-layer structure. The band gap energy values of TiO2 thin film and TiO2–W–TiO2 multi-layer thin films are evaluated from (αhν)1/2 versus energy plots, and the calculated results show that the energy gap decreases from 3.21 eV (TiO2 thin film) to 3.08∼3.03 EV (TiO2–W–TiO2 multi-layer thin films). 相似文献
9.
Libin Mo Yongjun Chen Lijie Luo 《Applied Physics A: Materials Science & Processing》2010,100(1):129-134
ZnO films were deposited by RF magnetron sputtering at the substrate temperature of 120∼420°C. XRD measurements revealed the
improvement of crystalline quality and grain size of the films with substrate temperature. The dielectric function of the
films was determined by fitting the experimental transmission spectra with Tauc–Lorentz (TL) model and a single Lorentzian
oscillator (SLO) dispersion function in the energy range of 1∼5 eV. The optical properties of the ZnO films strongly depended
on the substrate temperature. The optical band gap and the Penn gap of the ZnO films increased with the substrate temperature.
The band gap of the ZnO films indicated a direct interband transition between the valence and conduction band, and the change
of the in-plane film stress promoted the enhancement of the band gap. These results of the optical properties of the ZnO films
might be very meaningful to the application in the window design in solar cells. 相似文献
10.
Molybdenum oxide films (MoO3) were deposited on glass and crystalline silicon substrates by sputtering of molybdenum target under various oxygen partial pressures in the range 8 × 10−5–8 × 10−4 mbar and at a fixed substrate temperature of 473 K employing dc magnetron sputtering technique. The influence of oxygen partial pressure on the composition stoichiometry, chemical binding configuration, crystallographic structure and electrical and optical properties was systematically studied. X-ray photoelectron spectra of the films formed at 8 × 10−5 mbar showed the presence of Mo6+ and Mo5+ oxidation states of MoO3 and MoO3−x. The films deposited at oxygen partial pressure of 2 × 10−4 mbar showed Mo6+ oxidation state indicating the films were nearly stoichiometric. It was also confirmed by the Fourier transform infrared spectroscopic studies. X-ray diffraction studies revealed that the films formed at oxygen partial pressure of 2 × 10−4 mbar showed the presence of (0 k 0) reflections indicated the layered structure of α-phase MoO3. The electrical conductivity of the films decreased from 3.6 × 10−5 to 1.6 × 10−6 Ω−1 cm−1, the optical band gap of the films increased from 2.93 to 3.26 eV and the refractive index increased from 2.02 to 2.13 with the increase of oxygen partial pressure from 8 × 10−5 to 8 × 10−4 mbar, respectively. 相似文献
11.
H. Kim G. P. Kushto R. C. Y. Auyeung A. Piqué 《Applied Physics A: Materials Science & Processing》2008,93(2):521-526
Fluorine-doped tin oxide (FTO) thin films have been investigated as an alternative to indium tin oxide anodes in organic photovoltaic
devices. The structural, electrical, and optical properties of the FTO films grown by pulsed laser deposition were studied
as a function of oxygen deposition pressure. For 400 nm thick FTO films deposited at 300°C and 6.7 Pa of oxygen, an electrical
resistivity of 5×10−4 Ω-cm, sheet resistance of 12.5 Ω/□, average transmittance of 87% in the visible range, and optical band gap of 4.25 eV were obtained. Organic photovoltaic (OPV)
cells based on poly(3-hexylthiophene)/[6,6]-phenyl-C61-butyric acid methyl ester bulk heterojunctions were prepared on FTO/glass electrodes and the device performance was investigated as a function of FTO
film thickness. OPV cells fabricated on the optimum FTO anodes (∼300–600 nm thick) exhibited power conversion efficiencies
of ∼3%, which is comparable to the same device made on commercial ITO/glass electrodes (3.4%). 相似文献
12.
M. F. Al-Kuhaili S. M. A. Durrani I. A. Bakhtiari 《Applied Physics A: Materials Science & Processing》2010,98(3):609-615
Thin films of molybdenum oxide were deposited in vacuum by pulsed laser ablation using a xenon fluoride (351 nm) and a krypton
fluoride (248 nm) excimer lasers. The films were deposited on unheated substrates and were post-annealed in air in the temperature
range 300–500°C. The structural, morphological, chemical, and optical properties of the films were studied. As-deposited films
were found to be dark. The transparency of the films was improved with annealing in air. The films were polycrystalline with
diffraction peaks that belong to the orthorhombic phase of MoO3. The surface morphology of the films showed a layered structure. Both the grain size and surface roughness increased with
annealing temperature. The stoichiometry of the films improved upon annealing in air, with the best stoichiometry of MoO2.95 obtained for films deposited by the XeF laser and annealed at 400°C. Similarly, the best transparency, with a transmittance
exceeding 80%, was obtained with the films annealed in the temperature range 400–450°C. 相似文献
13.
Optical properties of molybdenum oxide thin films deposited by?chemical vapor transport of MoO3(OH)2
Young Jung Lee Young Ik Seo Se-Hoon Kim Dae-Gun Kim Young Do Kim 《Applied Physics A: Materials Science & Processing》2009,97(1):237-241
MoO3 thin films are useful for optical devices due to their electrochromic properties. In this study, deposition of MoO2 thin films was successfully accomplished by chemical vapor transport (CVT) of volatile MoO3(OH)2. Subsequently, a MoO3 thin film was obtained by annealing of the deposited MoO2 at 400°C in an O2 atmosphere. As annealing commenced, the optical transmittance of the films increased and their absorbance peaks were broadened
and red-shifted due to reduced oxygen vacancy. Thus, the molybdenum oxide thin films can successfully be deposited using the
CVT technique. 相似文献
14.
I. Navas R. Vinodkumar V. P. Mahadevan?Pillai 《Applied Physics A: Materials Science & Processing》2011,103(2):373-380
We report on the synthesis of self-assembled hillock shaped MoO3 nanoparticles on thin films exhibiting intense photoluminescence (PL) by RF magnetron sputtering and subsequent oxidation.
MoO3 nanocrystals of size ∼29 nm are self-assembled into uniform nanoparticles with diameter ∼174 nm. The mechanism of the intense
PL behaviour from MoO3 nanoparticles is investigated and systematically discussed. The films exhibit two bands; a near-band-edge UV emission and
a defect related deep level visible emission. The enhancement in PL intensity with annealing is not only by the improvement
in crystallinity and grain size but also by the increase in the rms surface roughness and porosity of the films. The PL intensity
is thermally activated with activation energy 1.07 and 0.87 eV respectively for the UV and visible emissions. The UV band
exhibits a blue shift according to the band gap with increasing post-annealing temperatures, which suggests the possibility
to tune the UV photoluminescence band by varying the oxidation temperature. 相似文献
15.
Infrared (IR) and UV spectra of ternary Li2O–CuO–P2O5 glasses in two series Li2O(65−X)%–CuO(X%)–P2O5(35%), X = 20, 30, 40 and Li2O(55−X)%–CuO(X%)–P2O5(45%), X = (10, 20, 30) were studied. Infrared (IR) investigations showed the metaphosphate and pyrophosphate structures and with
increase of CuO content in metaphosphate glass, the skeleton of metaphosphate chains is gradually broken into short phosphate
groups such as pyrophosphate. IR spectra showed one band at about 1,220 and 1,260 cm−1 for P2O5(35%) and P2O5(45%) series, respectively, assigned to P=O bonds. For CuO additions ≤20 mol%, the glasses exhibit two bands in the frequency
range 780–720 cm−1 which are attributed to the presence of two P–O–P bridges in metaphosphate chain. But for CuO addition ≥30 mol%, the glasses
exhibit only a single band at 760 cm−1 which is assigned to the P–O–P linkage in pyrophosphate group. In optical investigations, absorption coefficient versus photon
energy showed three regions: low energy side, Urbach absorption, and high energy side. In Urbach’s region, absorption coefficient
depends exponentially on the photon energy. At high energy region, optical gap was calculated and investigations showed indirect
transition in compounds and decreases in optical gap with increases of copper oxides contents that is because of electronic
transitions and increasing of nonbridging oxygen content. 相似文献
16.
Molybdenum oxide (MoO3) films were deposited on glass and (1 1 1) silicon substrates by sputtering of metallic molybdenum target in an oxygen partial pressure of 2 × 10−4 mbar and different substrate temperatures in the range 303-623 K using dc magnetron sputtering technique. X-ray photoelectron spectrum of the films formed at 303 K showed asymmetric Mo 3d5/2 and Mo 3d3/2 peaks due to the presence of mixed oxidation states of Mo5+ and Mo6+ while those deposited at substrate temperatures ≥473 K were in Mo6+ oxidation state of MoO3. The films formed at substrate temperatures ≥473 K were polycrystalline in nature with orthorhombic α-phase MoO3. Fourier transform infrared spectra of the films showed an absorption band at 1000 cm−1 correspond to the stretching vibration of MoO, the characteristic of the α-MoO3 phase. The electrical resistivity increased from 3.3 × 103 to 8.3 × 104 Ω cm with the increase of substrate temperature from 303 to 473 K respectively due to improvement in the crystallinity of the films. Optical band gap of the films increased from 3.03 to 3.22 eV with the increase of substrate temperature from 303 to 523 K. 相似文献
17.
Thin films of SnO2 were deposited by RF-magnetron sputtering on quartz substrates at room temperature in an environment of Ar and O2. The XRD pattern shows amorphous nature of the as-deposited films. The optical properties were studied using the reflectance and transmittance spectra. The estimated optical band gap (Eg) values increase from 4.15 to 4.3 eV as the Ar gas content decreases in the process gas environment. The refractive index exhibits an oscillatory behavior that is strongly dependent on the sputtering gas environment. The Urbach energy is found to decrease with increase in band gap. The band gap is found to decrease on annealing the film. The role of oxygen defects is explored in explaining the variation of optical parameters. 相似文献
18.
M. A. Algatti R. P. Mota R. Y. Honda M. E. Kayama K. G. Kostov R. S. Fernandes T. C.A.M. Azevedo N. C. Cruz 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,54(2):325-328
This paper deals with plasma polymerization processes of diethylene glycol dimethyl ether. Plasmas were produced at 150 mtorr
in the range of 10 W to 40 W of RF power. Films were grown on silicon and quartz substrates. Molecular structure of plasma
polymerized films and their optical properties were analyzed by Fourier transform infrared spectroscopy (FTIR) and ultraviolet-visible
spectroscopy. The IR spectra show C–H stretching at 3000–2900 cm-1, C=O stretching at 1730–1650 cm-1, C–H bending at 1440–1380 cm-1, C–O and C–O–C stretching at 1200–1000 cm-1. The concentrations of C–H, C–O and C–O–C were investigated for different values of RF power. It can be seen that the C–H
concentration increases from 0.55 to 1.0 au (arbitrary unit) with the increase of RF power from 10 to 40 W. The concentration
of C–O and C–O–C decreases from 1.0 to 0.5 au in the same range of RF power. The refraction index increased from 1.47 to 1.61
with the increase of RF power. The optical gap calculated from absorption coefficient decreased from 5.15 to 3.35 eV with
the increase of power. Due to its optical and hydrophilic characteristics these films can be applied, for instance, as glass
lens coatings for ophthalmic applications. 相似文献
19.
C. G. Jin T. Yu Z. F. Wu F. Wang M. Z. Wu Y. Y. Wang Y. M. Yu L. J. Zhuge X. M. Wu 《Applied Physics A: Materials Science & Processing》2012,106(4):961-966
Al-doped zinc oxide (AZO) films are prepared on quartz substrates by dual-ion-beam sputtering deposition at room temperature
(∼25°C). An assisting argon ion beam (ion energy E
i
=0–300 eV) directly bombards the substrate surface to modify the properties of AZO films. The effects of assisted-ion beam
energy on the characteristics of AZO films were investigated in terms of X-ray diffraction, atomic force microscopy, Raman
spectra, Hall measurement and optical transmittance. With increasing assisting-ion beam bombardment, AZO films have a strong
improved crystalline quality and increased radiation damage such as oxygen vacancies and zinc interstitials. The lowest resistivity
of 4.9×10−3Ω cm and highest transmittance of above 85% in the visible region were obtained under the assisting-ion beam energy 200 eV.
It was found that the bandgap of AZO films increased from 3.37 to 3.59 eV when the assisting-ion beam energy increased from
0 to 300 eV. 相似文献
20.
Prabitha B. Nair V.B. Justinvictor Georgi P. Daniel K. Joy V. Ramakrishnan P.V. Thomas 《Applied Surface Science》2011,257(24):10869-10875
TiO2 thin films were deposited onto quartz substrates by RF magnetron sputtering. The samples deposited at various RF powers and sputtering pressures and post annealed at 873 K, were characterized using X-ray diffraction (XRD), micro Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), UV-vis spectroscopy and photoluminescence (PL) spectroscopy. XRD spectrum indicates that the films are amorphous-like in nature. But micro-Raman analysis shows the presence of anatase phase in all the samples. At low sputtering pressure, increase in RF power favors the formation of rutile phase. Presence of oxygen defects, which can contribute to PL emission is evident in the XPS studies. Surface morphology is much affected by changes in sputtering pressure which is evident in the SEM images. A decrease in optical band gap from 3.65 to 3.58 eV is observed with increase in RF power whereas increase in sputtering pressure results in an increase in optical band gap from 3.58 to 3.75 eV. The blue shift of absorption edge in all the samples compared to that of solid anatase is attributed to quantum size effect. The very low value of extinction coefficient in the range 0.0544-0.1049 indicates the excellent optical quality of the samples. PL spectra of the films showed emissions in the UV and visible regions. 相似文献