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1.
Different thickness MgO thin films were grown on the glass substrate by successive ionic layer adsorption and reaction (SILAR) method as the first study in literature. X-ray diffraction (XRD) measurements demonstrate the cubic MgO structures and samples have (002), and (220) peaks. All film has nanoball structures observed from the scanning electron microscope (SEM) images. The band gap and transmittance values of MgO thin films decrease with increasing thickness. The photoluminescence (PL) spectrum demonstrates that samples have three visible emissions changing with thickness at 381?nm violet emission, 457?nm blue emission and 535?nm green emission. X-ray photoelectron spectroscopy (XPS) spectrum present confirms the elemental signals from carbon (C), oxygen (O) and magnesium (Mg) atoms in the sample. Both Moss and Herve and Vandamme relations refractive index values n, ε0, and ε values and amount of oxygen increase with raising thickness of MgO thin films.  相似文献   

2.
《Ceramics International》2023,49(18):30347-30354
Undoped and Cr-doped TiO2 thin films were synthesized by the dip-coating sol-gel process with titanium isopropoxide and chromium (III) chloride hexahydrate being used as the precursors. The chromium concentrations changed for different molar ratios, namely, 2, 4, and 8 wt.%. The samples, coated on glass substrates, were later annealed in air at 450 °C for 60 min. The influence of Cr doping on the structural, surface chemical, and optical properties of the samples was studied by several techniques, including EDS, Raman, UV–Vis, RT-PL, and XPS spectroscopies, as well as SEM and XRD. The diffraction patterns indicated that all the films displayed the anatase structure with the crystallite size decreasing with chromium doping. The same structure was confirmed by Raman spectroscopy measurements. UV–Vis absorption spectra of the samples showed a red shift of the fundamental absorption edge in the visible range following the increase of Cr doping concentration. In addition, the RT-PL study revealed that the dopant incorporation causes a decrease in the PL intensity. The EDS analysis revealed the presence of Ti, O, and Cr in the materials. Moreover, from high-resolution XPS Ti 2p spectra, titanium was found to be in the Ti4+ oxidation state evidencing the formation of TiO2, while the Cr 2p fitting analysis showed that chromium is present in the Cr (III) and Cr-metal states.  相似文献   

3.
《Ceramics International》2016,42(13):14581-14586
Aluminum and gallium co-doped ZnO (AGZO) thin films were grown by simple, flexible and cost-effective spray pyrolysis method on glass substrates at a temperature of 230 °C. Effects of equal co-doping with aluminum (Al) and gallium (Ga) on structural, optical and electrical properties were investigated by X-ray diffraction (XRD), UV–vis–NIR spectrophotometry and Current–Voltage (I–V) measurements, respectively. XRD patterns showed a successful growth with high quality polycrystalline films on glass substrates. The predominant orientation of the films is (002) at dopant concentrations ≤2 at% and (101) at higher dopant concentrations. Incorporation of Al and Ga to the ZnO crystal structure decreased the crystallite size and increased residual stress of the thin films. All films were highly transparent in the visible region with average transmittance of 80%. Increasing doping concentrations increased the optical band gap, from 3.12 to 3.30 eV. A blue shift of the optical band gap was observed from 400 nm to 380 nm with increase in equal co-doping. Co-doping improved the electrical conductivity of ZnO thin films. It has been found from the electrical measurements that films with dopant concentration of 2 at% have lowest resistivity of 1.621×10−4 Ω cm.  相似文献   

4.
《Ceramics International》2017,43(18):16593-16599
In the present study, nickel-doped zinc oxide thin films (ZnO:Ni) at different percentages (0–10%) were deposited on glass substrates by using a chemical spray technique. The effect of Ni concentration on the structural and optical properties of the ZnO:Ni thin films was investigated. The effect of Ni contents on the crystalline structure and optical properties of the films was systematically investigated by X-ray diffraction (XRD), scanning electronic microscopy (SEM), UV–vis, Photoluminescence spectra PL, and Raman spectrometry. The XRD analysis showed that both the undoped and Ni-doped ZnO films were crystallized in the hexagonal structure with a preferred orientation of the crystallites along the [002] direction perpendicular to the substrate. The XRD analysis also showed that the films were well crystallized in würtzite phase with the crystallites preferentially oriented towards (002) direction parallel to the c-axis. SEM study reveals the surface of NiZnO to be made of nanocrystalline particles. The SEM images showed a relatively dense surface structure composed of crystallites in the spherical form whose average size decreases when the [Ni]/[Zn] ratio increases. The optical study showed that all the films were highly transparent. The band gap decreased up to the 7 at% Ni doping level, but the band gap increased after 10 at% Ni doping level. All thin films exhibited approximately 80% and above transmittance in the visible region. PL spectra of undoped and Ni-doped ZnO thin films showed some marked peaks at 376, 389, 494, and 515 nm. The obtained results revealed that the structures and optical properties of the films were greatly affected by doping levels. These films are useful as conducting layers in electro chromic and photovoltaic devices. Finally, all results were discussed in terms of the nickel doping concentration.  相似文献   

5.
Undoped and nickel (Ni)-doped ZnO thin films were spray deposited on glass substrates at 523 K using 0.1 M of zinc acetate dihydrate and 0.002–0.01 M of nickel acetate tetrahydrate precursor solutions and subsequently annealed at 723 K. The effect of Ni doping in the structural, morphological, optical and electrical properties of nanostructured ZnO thin film was investigated using X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), UV–vis Spectrophotometer and an Electrometer respectively. XRD patterns confirmed the polycrystalline nature of ZnO thin film with hexagonal wurtzite crystal structure and highly oriented along (002) plane. The crystallite size was found to be increased in the range of 15–31 nm as dopant concentration increased. The SEM image revealed the uniformly distributed compact spherical grains and denser in the case of doped ZnO thin films. All the films were highly transparent with average transmittance of 76%. The measured optical band gap was found to be varied from 3.21 to 3.09 eV. The influence of Ni doping in the room temperature ethanol sensing characteristics has also been reported.  相似文献   

6.

Pure and Al-doped Zin Oxide ZnO (AZO) thin films with different aluminum (Al) concentrations (0.5, 1, 2, and 3 at.%) were prepared on glass substrates by a dip-coating technique using different Zn and Al precursors. The structural, morphological, optical and electrical properties of these films were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), Atomic force electron microscopy, ultraviolet–visible spectrophotometry, photoluminescence (PL) spectroscopy and four-point probe technique. XRD results showed that the obtained AZO thin films were polycrystalline with a highly c-axis preferred (002) orientation, and the average crystallites size decreased from 29 to 25 nm with the increase in Al doping concentration. EDS microanalysis confirmed the presence of Zn, O and Al elements in the prepared films as expected. The optical study demonstrated that the ZnO thin film had a good transparency in the visible range with a maximum transmittance of 90% and the band gaps varied from 3.16 to 3.26 eV by Al doping. SEM micrographs showed a wrinkles-like morphology of the thin films that changed in density with the increase of Al concentrations. The PL emission spectra indicated that except the thin film doped with 1 at.%, other films exhibited high emission intensities under an excitation of 325 nm which allows to apply them as downconversion layers for solar cell applications.

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7.
This study reports on the deposition of highly transparent, n-type ZnO thin films on glass substrate at 450?°C using spray pyrolysis processing, with the simultaneous insertion of yttrium (Y) at different percentages (0, 2, 5, 7?at%) as a dopant. The effect of Y doping on the structure, morphology and optical properties of Y doped ZnO (ZnO:Y) was investigated for optoelectronic applications. The obtained thin films were characterized by means of X-ray diffraction, field-emission scanning electron microscopy (FESEM), UV–visible absorbance measurements, photoluminescence (PL) and cathodoluminescence (CL) spectroscopy. The as-prepared films exhibit well-defined hexagonal wurtzite structure grown along [002]. Field emission scanning electron microscope micrographs of the pure ZnO and ZnO:Y showed that the films acquired a dominance of hexagonal-like grains, the morphology was influenced by Y incorporation. All the films showed high transparency in the visible domain with an average transmittance of 83%. The band gap energy, Eg, increased from 3.12?eV to 3.18?eV by increasing the Y doping concentration up to 5?at% and then decreased to 3.15?eV for 7?at% Y content. The PL and CL measurements reveal a strong ultraviolet (UV) emission, suggesting that the as-prepared ZnO:Y thin films can potentially be used in optoelectronic devices.  相似文献   

8.
《Ceramics International》2022,48(3):3751-3756
Beta-gallium oxide (β-Ga2O3) thin films were prepared on a MgO (100) substrate under different oxygen flow ratios via magnetron sputtering. X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and UV–visible near-infrared (UV–vis–NIR) analyses were conducted to study how the oxygen flow ratio affected the crystalline quality and the surface topography of the films. Microstructure analysis revealed a clear out-of-plane orientation of β-Ga2O3 (100) || MgO (100). The film deposited under an oxygen flow ratio of 1% presented the optimal single-crystalline structure, while excess oxygen was confirmed to negatively impact the crystallization characteristics of the films. SEM measurements indicated that the increase in the oxygen flow ratio reduced the grain size and RMS roughness. The average transmittance of the β-Ga2O3 films in the visible range exceeded 83%, with a broad luminescence band exhibited at approximately 485 nm in the photoluminescence (PL) spectra.  相似文献   

9.
《Ceramics International》2023,49(8):12231-12239
Ultra-rapid microwave-assisted hydrothermal synthesis was performed, zinc oxide nanoparticles were fabricated and doped with gallium. Different times (5, 15, and 30 min) and concentrations of doped Ga (1, 3, and 6%) were used to improve their characteristic properties. In addition, the relation between time/dopant was analyzed. The samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, and UV–Vis diffuse reflectance spectroscopy. Photoluminescence (PL) to verify number of defects. SEM analysis showed the formation of nanorods morphology even with a short synthesis time. The X-ray diffractograms and Raman spectra suggest the successful insertion of Ga into the ZnO lattice. The crystallite size obtained by doping was between 36 and 50 nm. The lattice parameters determined by the Rietveld refinement confirmed the formation of a wurtzite hexagonal structure. The band gap range found was 3.12–3.22 eV, which increases the potential of ZnO for optical applications. The presence of defects as result of doping was confirmed by PL. The microstructural changes of the material are enhanced by doping, which causes the photocurrent to increase from 0,002 to 0.012 mA/cm2 in doped ZnO. The synthesis time and Ga doping facilitated the production of ZnO nanoparticles with improved properties.  相似文献   

10.
《Ceramics International》2017,43(15):12162-12166
Pure and erbium doped (1, 2, 3 and 5 at%) Barium zirconate (BZE) thin films have been deposited on Si (0 0 1) substrate via pulsed laser deposition using 100 mJ Nd: YAG laser operated at second harmonics (532 nm). Er doping significantly affects the surface morphology, microstructure and optical properties of grown thin films. All the films exhibit cubic BaZrO3 structure and are polycrystalline in nature as extracted from XRD data. The optical band gap energies (3.75–3.63 eV) of doped (1, 2, 3, and 5 at%) BZE thin films are found to be less than that of pure BZO film (4.03 eV). PL spectra, excited at 328 nm, mainly consist of violet-blue (412 nm) and green (523–543 nm) emissions for all the doped films. The green emission increases with the increase in Er doping upto 3 at% and then concentration quenching effect appears at 5 at%. It is noted that the relative intensity of PL emission and the optical band gap can be tuned by varying Er concentration to alter the properties of the phosphor. The emission peaks in photoluminescence spectra makes the Er: BZO films potential candidates to be used in optoelectronic devices such as light emitting diodes (LEDs).  相似文献   

11.
《Ceramics International》2023,49(3):4230-4239
The work focuses on exploring the effect of the concentration of Sm dopant (0.2–0.6 at.%) on structural, optical and photocatalytic properties of the spin coated titania based thin films annealed at different temperatures. The optical interpretation involves the influence of Sm doping on optical constants and luminescence behaviour of the samples. The comprehensive work on optical bandgap, Urbach energy and electron-phonon interaction strength was conducted for Sm doped samples. The optical band gap was found to increase with the increasing concentration of Sm, but decreased with high temperature annealing. Using ellipsometry measurement, refractive index of the samples was obtained. The orbital level information was gathered using X-Ray Photoelectron Spectroscopy (XPS) study with a special emphasis on the evolution of physico-chemical properties as function of Sm doping. The XPS study confirms the presence of Sm in the titania host material and it helped in estimating defects induced by Sm doping. The photocatalytic study of Sm doped titania thin films was carried out by using methylene blue (MB) and Rhodamine B (RhB) dye and we have found an enhanced photocatalytic activity for the 0.4 at.% Sm doped samples.  相似文献   

12.
Herein, we report the photosensing property of CdS thin films. CdS thin films were coated onto glass substrates via a spray pyrolysis method using different spray pressures. Prepared films were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and optical and photoluminescence spectroscopy. XRD analysis demonstrated the growth of crystalline CdS films with crystallite sizes varying from 26 to 29 nm depending on the pressure. The SEM and EDAX analyses revealed nearly-stoichiometric CdS films with smooth surfaces and slight variation in grain morphology due to pressure changes. Optical measurements showed a direct bandgap varying from 2.37 eV to 2.42 eV due to pressure changes. A photodetector was also fabricated using the grown CdS films; the fabricated photodetector exhibited good performance depending on the spray pressure. A spray pressure of 1.5 GPa resulted in high photoresponsivity and external quantum efficiency.  相似文献   

13.
Manganese‐doped tin oxide (SnO2:Mn) thin films were deposited on glass substrates by the sol–gel dip coating technique. The effect on structural, morphological, magnetic, electrical, and optical properties in the films with different Mn concentrations (0–5 mol%) were investigated. X‐ray diffraction patterns (XRD) showed the deterioration of crystallinity with increase in Mn‐doping concentration. Scanning electron microscopy (SEM) studies showed an inhibition of grain growth with an increase in Mn concentration. X ray photoelectron spectroscopy (XPS) revealed the presence of Sn4+ and Mn3+ in SnO2: Mn films. SnO2: Mn films show ferromagnetic and paramagnetic behavior. These SnO2:Mn films acquire n‐type conductivity for 0–3 mol% (SnO2 ‐ Sn0.97Mn0.03O2) ‐doping concentration and p type for 5 mol% Mn‐doping concentration(Sn0.95Mn0.05O2) in SnO2 films. An average transmittance of > 75% (in UV‐Vis region) was observed for all the SnO2:Mn films. Optical band gap energy of SnO2: Mn films were found to vary in the range 3.55 to 3.71 eV with the increase in Mn‐doping concentration. Photoluminescence (PL) spectra of the films exhibited an increase in the emission intensity with increase in Mn‐doping concentration which may be due to structural defects or luminescent centers, such as nanocrystals and defects in the SnO2. Such SnO2:Mn films with structural, magnetic and optical properties can be used as dilute magnetic semiconductors.  相似文献   

14.
《Ceramics International》2016,42(9):10847-10853
Ta-doped ZnO films with different doping levels (0–5.02 at%) were prepared by radio frequency magnetron sputtering. The effects of the doping amount on the microstructure and the optical properties of the films were investigated. The grain size and surface roughness first significantly decrease and then slowly increase with the increase of Ta doping concentration. Both the grain size and the root mean square (RMS) roughness reach their minimum values at the doping content of 3.32 at%. X-ray Diffraction (XRD) patterns confirmed that the prepared Ta-doped ZnO films are polycrystalline with hexagonal wurtzite structure and a preferred orientation along the (002) plane. X-ray photoelectron spectroscopy (XPS) analysis reveals that Ta exists in the ZnO film in the Ta5+ and Ta4+ states. The average optical transmission values of the Ta-doped ZnO films are higher than those of the un-doped ZnO film in the visible region. The band gap energy extracted from the absorption edge of transmission spectra becomes large and the near band edge (NBE) emission energy obtained from PL spectra blueshifts to high energy when the Ta doping content grows from 0 at% to 5.02 at%, which can be explained by the Burstein–Moss shift.  相似文献   

15.
In this work, V-doped and (Sm, V) co-doped ZnO samples have been synthesized using ball milling method followed by heat treatment. The dependence of structural, optical, electrical and dielectric properties of V:ZnO samples on the Sm doping concentration has been explored. The structural properties have been studied by means of X-ray diffraction (XRD) and Rietveld refinement. Oxidation states of the elements present in the samples are determined using X-ray photoelectron spectroscopy. Raman spectra of the samples further verified the observations obtained from XRD. The crystallite size and microstrain have been estimated from the Williamson-Hall analysis. Microstrain increases from 0.814 × 10?3 to 1.01 × 10?3 with increase in the Sm doping level. The morphology of the grains is significantly affected by the Sm doping. The enhancement of defect density with Sm doping is responsible for the observed red shift (3.29–3.19 eV) in the band gap. The frequency dependence of the dielectric properties has been studied at various fixed temperatures ranging from 25 to 350 °C. The increase in real dielectric constant with dopant content indicates the enhancement of energy storage capacity. The ac conductivity follows Jonscher's power law and it increases up to 1 mol% Sm concentration. Further increase in Sm extent leads to the decrease in ac conductivity. The impedance spectroscopy has been performed to understand electrical behavior of samples and Cole-Cole plots are fitted against the equivalent circuit model. The electrical activation energy values for conduction and relaxation vary in the range: 0.281–0.269 eV and 0.260–0.243 eV, respectively.  相似文献   

16.
We report the effect of Ti-doping on structural, morphological, photoluminescence, optical and photoconductive properties of ZnO thin films. Pure and Ti(1, 3 and 5%)-doped ZnO thin films are deposited by the successive ionic layer adsorption and reaction (SILAR) method. The X-ray diffraction analysis revealed the single-phase hexagonal wurtzite ZnO structure of all the films. Scanning electron microscope images suggest the formation of rod shaped particles in Ti-doped ZnO thin films. Photoluminescence spectra of all the films show emission peaks centered at 398 nm, 413 nm, 438 nm, 477 nm and 522 nm wavelengths. Optical properties support the semiconducting nature of all the films. The optical bandgap values are estimated to be 3.29 eV, 3.26 eV, 3.19 eV and 3.23 eV for ZnO, ZnO:Ti(1%), ZnO:Ti(3%) and ZnO:Ti(5%) thin films, respectively. Photoconductivity study indicates that ZnO:Ti(3%) thin film exhibits high responsivity, external quantum efficiency and detectivity of 0.30 AW-1, 97% and 5.49 × 1010 Jones, respectively, among all the films. The enhanced photoconductivity of Ti-doped ZnO thin films make them useful for optoelectronic applications.  相似文献   

17.
《Ceramics International》2017,43(17):14983-14988
Undoped and S-doped Cu3Se2 nanostructures (NSs) with different sulfur concentrations were synthesized by a green, simple, and cost-effective co-precipitation method in ambient conditions. X-ray diffraction patterns (XRD) of the samples indicated that, all samples had a tetragonal phase of Cu3Se2. Fourier transform infrared spectroscopy (FTIR) results revealed that, some vibration modes were appeared by sulfur. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images showed that, sulfur had a significant role to change of morphology of the products. UV–vis and Photoluminescence (PL) results showed that, the band gap value of the pristine sample was 1.72–1.85 eV, while S-doped (4%) sample had a band-gap value between 1.61 eV and 1.67 eV. On the other hand, further increase of sulfur up to 6% caused band gap value increase in compared to the 4% sulfur doped. In addition, the PL results revealed that, the products had surface-trap states (STS) energy as well as different intrinsic defects such as Cu-vacancy. Furthermore, the PL spectrum of the S-doped sample showed that, sulfur ions caused increase natural donor-acceptor (D°→A°) recombination energy intensity. Finally, photocatalytic measurements showed that, the photocatalytic performance of the samples under solar-light irradiation was enhanced by an increase of sulfur concentration up to 4%.  相似文献   

18.
《Ceramics International》2023,49(4):5728-5737
Highly transparent and conductive pure (SnO2) and aluminum doped tin oxide (Al:SnO2) thin films were deposited on glass substrates by the sol-gel spin-coating method. The structural, morphological, optical and electrical properties of the prepared thin films at different doping rates have been studied. X-ray diffraction results revealed that all the films were polycrystalline in nature with a tetragonal rutile structure. SEM images of the analyzed films showed a homogeneous surface morphology, composed of nanocrystalline grains. The EDS results confirmed the presence of Sn and O elements in pure SnO2 and Sn, O, Al in doped SnO2 thin films. The optical results revealed a high transmittance greater than 85% in the visible and near infrared and a band gap varying between 3.82 and 3.89 eV. PL spectra at room temperature showed that the most dominant defects correspond to oxygen vacancies. A low resistivity of order varying between 10?3 and 10?4 Ω cm and a high figure of merits ranging between 10?3 and 10?2 Ω?1 in the visible range were obtained. The best performances were obtained for samples containing 2 at. % Al, which could be used as an alternative TCO layer for future optoelectronic devices.  相似文献   

19.
《Ceramics International》2015,41(4):5688-5695
Cryptomelane type manganese oxide α-MnO2 and Ni doped KMn8O16 nanostructures were synthesized by water-bathing methods at 80 °C for 24 h using NiSO4·H2O as the dopant sources. The structures, morphologies and physical properties were investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The results show that the products are Ni doped KMn8O16 nanorods after the introduction of NiSO4·H2O during the reaction process. The electromagnetic characteristics and microwave absorption properties of the materials were carried out with a vector network analyzer (VNA) and the transmission line (TML) theory. The dielectric loss and microwave absorption properties of the cryptomelane materials are improved after Ni doping. The thickness dependent reflection loss shows that the peak frequency and effective absorption bandwidth all decrease with the increasing material thickness. With the increase of Ni doping concentration, the peak frequency shifts to higher frequency bands and the effective absorption bandwidth increases. The electromagnetic performance of cryptomelane can be attributed to its unique tunnel structures and the improvement of Ni doping can be due to the enhanced electromagnetic polarization.  相似文献   

20.
《Ceramics International》2022,48(10):13420-13430
Treatment of waste water via photocatalysis is one of the most effective, economical and environment friendly process. In this study, green method (leaf extract of Citrus Medica Linn.) is used to synthesize pure and lanthanum (La)-(1,2 & 3 wt%) doped copper oxide nanoparticles (CuO-NPs). Different characterization techniques such as XRD, SEM, EDS, UV/VIS, PL and FTIR are utilized to investigate their physical, chemical, optical and structural properties. The synthesized material is used as photocatalyst for degradation of methylene blue (MB) dye. Interestingly, the La doped CuO-NPs have exhibited unique results. Variation in dopant concentration reduces the particle size (40.82 ± 0.04 nm to 31.89 ± 0.02 nm) and band gap of material shifts towards visible region (3.03 eV–2.71 eV). During photocatalysis, doping reduces the electron-hole pair recombination rate which makes it a potential photocatalyst. Maximum degradation efficiency of 84% is observed in 150 min for 2% La doped CuO-NPs which reveals that 2% La doping is optimal. Further increase in dopant concentration increases band gap, therefore, degradation efficiency drops to 75%. Simulation of this work is carried out using COMSOL Multiphysics 5.3a Licensed version. A 2D model is constructed and CuO-NPs is considered as photocatalyst in order to correlate simulated and experimental photocatalytic degradation of MB and rhodamine B (RhB) dye. Comparative analysis of rate constants revealed that the trend given by simulation is very close to the experimental observations.  相似文献   

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