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1.
The copper oxide films were deposited by decomposition of copper(II) acetylacetonate precursor in a hot wall horizontal flow tubular furnace by chemical vapor deposition method. The obtained data revealed change in phase of the deposits from crystalline copper(I) oxide (Cu 2O) to copper(II) oxide (CuO) structures on increasing the substrate temperature from 195 to 430 °C. The scanning electron microscope images showed the formation of mono-dispersed micron-sized Cu 2O cubical structures. The Cu 2O micro-cubes were observed to have a comparatively higher optical transmittance than CuO film in the visible spectral region. The Cu 2O micro-cubical films are expected to underlie the potential use as cost effective transparent conducting oxide electrode in solar cell applications. 相似文献
2.
Thin films of copper oxide were deposited by thermal evaporation of cuprous oxide (Cu 2O) powder. The substrates were either unheated or heated to a temperature of 300 °C. The films were also annealed in air at a temperature of 500 °C for 3 h. The films were characterized by X-ray photoelectron spectroscopy, X-ray diffraction and UV-visible spectrophotometry. The effects of the substrate temperature and post-deposition annealing on the chemical, structural and optical properties of the films were investigated. As-deposited films on unheated substrates consisted of mixed cupric oxide (CuO) and Cu 2O phases, with a higher concentration of the Cu 2O phase. However, the films deposited on heated substrates and the annealed films were predominantly of the CuO phase. 相似文献
3.
Cuprous oxide (Cu 2O) and cupric oxide (CuO) thin films were deposited on glass substrates at different oxygen partial pressures by direct-current reactive magnetron sputtering of pure copper target in a mixture of argon and oxygen gases. Oxygen partial pressure was found to be a crucial parameter in controlling the phases and, thus, the physical properties of the deposited copper oxide thin films. Single-phase Cu 2O thin films with cubic structure were obtained at low oxygen partial pressure between 0.147 Pa and 0.200 Pa while higher oxygen partial pressure promoted the formation of CuO thin films with base-centered monoclinic structure. Polycrystalline Cu 2O thin films deposited with oxygen partial pressure at 0.147 Pa possessed the lowest p-type resistivity of 1.76 Ω cm as well as an optical band gap of 2.01 eV. On the other hand, polycrystalline CuO thin films deposited with oxygen partial pressure at 0.320 Pa were also single phase but showed a n-type resistivity of 0.19 Ω cm along with an optical band gap of 1.58 eV. 相似文献
4.
Copper oxide, Cu 2O and CuO, thin films have been synthesized on Si (100) substrates using pulsed laser deposition method. The influences of substrate temperature and oxygen pressure on the structural properties of copper oxide films were discussed. The X-ray diffraction results show that the structure of the films changes from Cu 2O to CuO phase with the increasing of the oxygen pressure. It is also found that the (200) and (111) preferred Cu 2O films can be modified by changing substrate temperature. The formation of Cu 2O and CuO films are further identified by Fourier transform infrared spectroscopy. For the Cu 2O films, X-ray photoelectron spectroscopic studies indicate the presence of CuO on the surface. In addition, the optical gaps of Cu 2O and CuO films have been determined by measuring the transmittance and reflectance spectra. 相似文献
5.
N-doped Cu 2O films are deposited by sputtering a CuO target in the mixture of Ar and N 2. The structures zand optical properties have been studied for the films deposited at different temperatures. It is found that N-doping can suppress the formation of CuO phase in the films. The films are highly (100) textured at low temperatures and gradually change to be highly (111) textured at the temperature of 500 °C. With the analysis of (111) and (100) grain sizes, the surface free energy and grain size of critical nuclei are suggested to dominate the film texture. The analysis of the atomic force microscopy shows that the film growth can be attributed to the surface-diffusion-dominated growth. The forbidden rule of band gap transition is found disabled in the N-doped Cu 2O films, which can be attributed to the occupation of 2 p electrons of nitrogen at the top of valence band. The optical band gap energy is determined to be 2.52 ± 0.03 eV for the films deposited at different temperatures. 相似文献
6.
Cu/TiO 2 composite films were prepared at low temperature on glass substrates by a photodeposition method. Films were deposited by irradiating the substrate while in contact with an aqueous TiO 2 suspension containing copper(II) nitrate and ethanol. Cu/TiO 2 composite films of 500 nm in thickness were deposited at room temperature after a short irradiation time (15 min) with a 125 W mercury vapour lamp. According to scanning electron microscopy observations, the obtained films were homogeneous and porous. Energy dispersive X-ray spectroscopy analysis revealed a 3:1 Cu:Ti atomic ratio. Grazing angle X-ray diffraction analysis showed that the films contained Cu and TiO 2 as major components and Cu 2O as a minor component. Heat treatment at 400 °C in air for a period of 3 h transformed the initial material into a CuO/TiO 2 composite, improved the adhesion to the substrate and favoured a more regular distribution of copper oxide according to backscattering micrographs. 相似文献
7.
With the emergence of transparent electronics, there has been considerable advancement in n-type transparent semiconducting oxide (TSO) materials, such as ZnO, InGaZnO, and InSnO. Comparatively, the availability of p-type TSO materials is more scarce and the available materials are less mature. The development of p-type semiconductors is one of the key technologies needed to push transparent electronics and systems to the next frontier, particularly for implementing p-n junctions for solar cells and p-type transistors for complementary logic/circuits applications. Cuprous oxide (Cu 2O) is one of the most promising candidates for p-type TSO materials. This paper reports the deposition of Cu 2O thin films without substrate heating using a high deposition rate reactive sputtering technique, called high target utilisation sputtering (HiTUS). This technique allows independent control of the remote plasma density and the ion energy, thus providing finer control of the film properties and microstructure as well as reducing film stress. The effect of deposition parameters, including oxygen flow rate, plasma power and target power, on the properties of Cu 2O films are reported. It is known from previously published work that the formation of pure Cu 2O film is often difficult, due to the more ready formation or co-formation of cupric oxide (CuO). From our investigation, we established two key concurrent criteria needed for attaining Cu 2O thin films (as opposed to CuO or mixed phase CuO/Cu 2O films). First, the oxygen flow rate must be kept low to avoid over-oxidation of Cu 2O to CuO and to ensure a non-oxidised/non-poisoned metallic copper target in the reactive sputtering environment. Secondly, the energy of the sputtered copper species must be kept low as higher reaction energy tends to favour the formation of CuO. The unique design of the HiTUS system enables the provision of a high density of low energy sputtered copper radicals/ions, and when combined with a controlled amount of oxygen, can produce good quality p-type transparent Cu 2O films with electrical resistivity ranging from 10 2 to 10 4 Ω-cm, hole mobility of 1-10 cm 2/V-s, and optical band-gap of 2.0-2.6 eV. These material properties make this low temperature deposited HiTUS Cu 2O film suitable for fabrication of p-type metal oxide thin film transistors. Furthermore, the capability to deposit Cu 2O films with low film stress at low temperatures on plastic substrates renders this approach favourable for fabrication of flexible p-n junction solar cells. 相似文献
8.
In this work, self-assembled monolayers (SAMs) of octadecyltrichlorosilane (OTS) were applied to induce the nucleation and
growth of the antimony sulfide (Sb 2S 3) films on the functional ITO glass substrate at low temperature. The structure, morphology, and optical properties of the
Sb 2S 3 films were investigated by X-ray diffraction, scanning electron microscopy, X-ray energy dispersive spectroscopy, and UV–vis
spectroscopy. After thermal treatment at 200 °C for 1 h in air, the orthorhombic Sb 2S 3 was formed as a predominant phase in the deposited thin films. When the deposited films were thermally treated at 400 °C
for 1 h in air, the orthorhombic Sb 2S 3 was decomposed and a cubic Sb 2O 3 was formed. The optical band energies of the as-deposited and thermally treated Sb 2S 3 films at 200 °C for 1 h in air and nitrogen were found to be 2.05 eV, 1.77, and 1.76 eV, respectively. As chemical templates,
the OTS-functionalized SAMs played an important role in controlling the nucleation and growth of Sb 2S 3 films at low temperature. The results obtained from different preparation parameters applied in the present work will allow
controlling the growth of the Sb 2S 3 films with uniform surface. 相似文献
9.
Cerium dioxide (CeO 2) thin films were deposited on glass substrates by spray pyrolysis using a solution of alcohol–water and CeCl 3 · 7H 2O as precursor. The structural, morphological, optical and electrical properties of these films were investigated. SEM images
reveal the presence of cracks in the films that depend on substrate temperature and deposition time. Films deposited in temperatures
between 400 and 500 °C during up to 10 min are crack free and also present high optical transmittance, reaching up to 90%
in the visible range and close to infrared. X-ray diffraction shows that all films are polycrystalline and the growth preferential
direction is altered from (111) to (200) with the increase of the deposition temperature. The activation energy of the electrical
conduction process is 0.67 ± 0.03 eV. 相似文献
10.
The effects of substrate temperature and selenization temperature on the structure, composition, electrical and optical properties
of Cu 2SnSe 3 films were studied systematically. Cu 2SnSe 3 films deposited at various substrate temperatures (303–573 K) by the flash evaporation method are found to be non-stoichiometric.
To compensate the selenium deficiency and obtain a single-phase, an annealing Cu 2SnSe 3 films deposited at 573 K was performed in selenium atmosphere. Cu 2SnSe 3 films deposited at a substrate temperature of 573 K and then selenized at 673 K were single phase and polycrystalline exhibiting
monoclinic structure. The films showed p-type conductivity with a direct band gap of 0.84 eV. 相似文献
11.
Copper nitride (Cu 3N) films were deposited on glass substrates by sputtering of copper target under various substrate temperatures in the range
303–523 K using dc reactive magnetron sputtering. The substrate temperature highly influenced the structural, mechanical,
electrical and optical properties of the deposited films. The X-ray diffraction measurements showed that the films were of
polycrystalline nature and exhibit preferred orientation of (111) phase of Cu 3N. The microhardness of the films increased from 2.7 to 4.4 GPa with the increase of substrate temperature from 303 to 473 K
thereafter decreased to 4.1 GPa at higher temperature of 523 K. The electrical resistivity of the films decreased from 8.7 × 10 −1 to 1.1 × 10 −3 Ωcm and the optical band gap decreased from 1.89 to 1.54 eV with the increase of substrate temperature from 303 to 523 K
respectively. 相似文献
12.
The effect of process conditions on the composition and structure of anodic Cu 2O films grown in sulfate-chloride electrolytes has been studied using Auger electron spectroscopy, x-ray diffraction, and atomic force microscopy. The results demonstrate that the copper and oxygen depth profiles in the anodic copper(I) oxide films (ACOFs) are similar in shape. The copper content near the surface is only slightly lower than the bulk copper content. Starting at a depth of 9 nm, the Cu content is constant at an average of 62.7 at %. The Cu 2O films grown at a current density j = 3 mA/cm 2 have the most perfect stoichiometry, with deviations only in the surface layer. Anodic oxidation produces unoriented polycrystalline films of complex composition. In addition to Cu 2O, the films contain CuCl and trace levels of copper. Raising the anode current density influences, for the most part, the formation of (111)-oriented crystallites, changing their orientation from (111) to (220). We assume that nonmetal (oxygen or chlorine) atoms are incorporated into the cubic structure of copper without changing its symmetry but increasing its unit-cell parameter: from 0.3607 (Cu) to 0.426 (Cu 2O) and to 0.541 nm (CuCl). 相似文献
13.
Samarium oxide (Sm 2O 3) thin films with thicknesses in the range of 15–30 nm are deposited on n-type silicon (100) substrate via radio frequency
magnetron sputtering. Effects of post-deposition annealing ambient [argon and forming gas (FG) (90% N 2 + 10% H 2)] and temperatures (500, 600, 700, and 800 °C) on the structural and electrical properties of deposited films are investigated
and reported. X-ray diffraction revealed that all of the annealed samples possessed polycrystalline structure with C-type
cubic phase. Atomic force microscope results indicated root-mean-square surface roughness of the oxide film being annealed
in argon ambient are lower than that of FG annealed samples, but they are comparable at the annealing temperature of 700 °C
(Argon—0.378 nm, FG—0.395 nm). High frequency capacitance–voltage measurements are carried out to determine effective oxide
charge, dielectric constant and semiconductor-oxide interface trap density of the annealed oxide films. Sm 2O 3 thin films annealed in FG have smaller amount of effective oxide charge and semiconductor-oxide interface trap density than
those oxide films annealed in argon. Current–voltage measurements are conducted to obtain barrier heights of the annealed
oxide films during Fowler–Nordheim tunneling. 相似文献
14.
We fabricated CeO 2 films using pulsed laser deposition (PLD) for YBa 2Cu 3O 7−δ
coated conductors on Ni–5 at.%W alloy substrates and investigated the effect of Ni–5 at.%W tapes on the epitaxial growth
and surface morphologies of CeO 2 deposited on various substrates at various temperatures ranging from 650 to 770 °C. The texture and microstructure of substrates
and CeO 2 films were measured by X-ray diffraction (XRD), optical microscope (OM), field emission scanning electron microscope (FESEM)
and atomic force microscopy (AFM). It was found that the texture and microstructure of Ni–5 at.%W substrates, such as Ni(111),
grain size, the depth of grain boundary grooves and surface roughness, affected the growth of CeO 2 films. Especially, the depth of grain boundary grooves of substrates resulted in high intensity of CeO 2(111) peak and high surface roughness of CeO 2 films. We also found that high growth temperature effectively reduced the influence of substrate surface roughness on the
epitaxial growth of CeO 2 films. CeO 2 films with high in-plane and out-of-plane alignments (Δ φ=5.54°, Δ ω=3.40°) were obtained under optimum condition. 相似文献
15.
Plasmonic nanocomposite thin films find exciting applications in environmental remediation and photovoltaics. We report on thermal annealing driven development of morphology, structure and photocatalytic performance of Au–Cu2O–CuO nanocomposite thin film. Nanocomposite thin film coatings of Au–Cu2O–CuO, prepared by radio frequency (RF) magnetron co-sputtering, were annealed at different temperatures. Thermal annealing driven evolution of morphology of Au–Cu2O–CuO nanocomposite was studied by field emission scanning electron microscopy (FESEM), which revealed significant growth in size of nanostructures from 10 nm to 69 nm upon annealing. X-ray diffraction (XRD) together with Raman studies confirmed the nanocomposite nature of Au–Cu2O–CuO film. UV-visible diffuse reflectance spectroscopy (UV-vis-DRS) studies showed band gap variation from 2.44 eV to 1.8 eV upon annealing at 250 °C. Nanocomposite thin film annealed at 250 °C exhibited superior photocatalytic activity for organic pollutants [methylene blue (MB) and methyl orange (MO)] decomposition. The origins of thermal transformation of morphological, optical and photocatalytic behaviour of the Au–Cu2O–CuO nanocomposite coating are discussed. 相似文献
16.
In this study, effect of the post-deposition thermal annealing on copper oxide thin films has been systemically investigated. The copper oxide thin films were chemically deposited on glass substrates by spin-coating. Samples were annealed in air at atmospheric pressure and at different temperatures ranging from 200 to 600°C. The microstructural, morphological, optical properties and surface electronic structure of the thin films have been studied by diagnostic techniques such as X-ray diffraction (XRD), Raman spectroscopy, ultraviolet–visible (UV–VIS) absorption spectroscopy, field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). The thickness of the films was about 520 nm. Crystallinity and grain size was found to improve with annealing temperature. The optical bandgap of the samples was found to be in between 1.93 and 2.08 eV. Cupric oxide (CuO), cuprous oxide (Cu 2O) and copper hydroxide (Cu(OH) 2) phases were observed on the surface of as-deposited and 600 °C annealed thin films and relative concentrations of these three phases were found to depend on annealing temperature. A complete characterization reported herein allowed us to better understand the surface properties of copper oxide thin films which could then be used as active layers in optoelectronic devices such as solar cells and photodetectors. 相似文献
17.
The Cu 2O thin films were prepared on quartz substrate by reactive direct current magnetron sputtering. The influences of oxygen partial pressure and gas flow rate on the structures and properties of deposited films were investigated. Varying oxygen partial pressure leads to the synthesis of Cu 2O, Cu 4O 3 and CuO with different microstructures. At a constant oxygen partial pressure of 6.6 × 10 − 2 Pa, the single Cu 2O films can be obtained when the gas flow rate is below 80 sccm. The as-deposited Cu 2O thin films have a very high absorption in the visible region resulting in the visible-light induced photocatalytic activity. 相似文献
18.
In this study, electrochromic properties of cuprous oxide nanoparticles, self-accumulated on the surface of a sol-gel silica thin film, have been investigated by using UV-visible spectrophotometry in a lithium-based electrolyte cell. The cuprous oxide nanoparticles showed a reversible electrochromic process with a thin film transmission reduction of about 50% in a narrow wavelength range of 400-500 nm, as compared to the bleached state of the film. Using optical transmission measurement, we have found that the band gap energy of the films reduced from 2.7 eV for Cu 2O to 1.3 eV for CuO by increasing the annealing temperature from 220 to 300 °C in an N 2 environment for 1 h. Study of the band gaps of the as-deposited, colored and bleached states of the nanoparticles showed that the electrochromic process corresponded to a reversible red-ox conversion of Cu 2O to CuO on the film surface, in addition to the reversible red-ox reaction of the Cu 2O film. X-ray photoelectron spectroscopy indicated that the copper oxide nanoparticles accumulated on the film surface, after annealing the samples at 200 °C. Surface morphology of the films and particle size of the surface copper oxides have also been studied by atomic force microscopy analysis. The copper oxide nanoparticles with average size of about 100 nm increased the surface area ratio and surface roughness of the silica films from 2.2% and 0.8 nm to 51% and 21 nm, respectively. 相似文献
19.
Direct current reactive magnetron sputtering was used to deposit the thin layers of copper oxide (Cu 2O) on glass substrates. A solid disc of pure copper as the target was sputtered in an argon gas under sputtering pressures varying from 0.133 to 4 Pa. The effects of the sputtering power and pressure on the structural and optical properties of Cu 2O thin films were systematically studied. The deposited layers were characterized using X-ray diffraction, atomic force microscopy, profilometry and spectrophotometry. The optical transmission of the films was measured in the visible region. The increase in pressure resulted in a higher growth rate than increasing sputtering power. The increase in power produced Cu 2O thin films that were detrimental to the optical transmission of the films. 相似文献
20.
The formation behavior of CaCu 3Ti 4O 12 (CCTO) had been investigated via solid state reaction from CaTiO 3, CuO and TiO 2 powders. In the temperature range from 750 to 1,200 °C, the reaction sequence was traced by XRD, and the microstructure evolution
of calcined powders was also investigated by SEM. CCTO began to form owing to the reaction between CaTiO 3, CuO and TiO 2 at around 850 °C, and became the major phase at 1,000 °C. Finally, the single phase CCTO was obtained at 1,150 °C. However,
CCTO was decomposed at CaTiO 3, CuO and TiO 2 when the temperature increased to 1,200 °C. In addition, no other intermediate phases occurred in the synthesized process.
The formation behaviors indicated that CaTiO 3 prevented the formation and growth of CCTO. 相似文献
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