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1.
Cu2O films were electrodeposited on stainless steel substrates followed by Ar annealing for photoelectrochemical hydrogen generation. Plating variables including time and pH for the plating bath were explored to obtain desirable film qualities. X-ray diffraction (XRD) patterns indicated that the as-deposited Cu2O films exhibited preferred orientations in (200) and (111) planes from the plating bath of pH 9 and pH 11, respectively. Images from scanning electron microscope (SEM) revealed pyramid-like grains in 1 µm size for the Cu2O films from pH 9 plating bath and large plate-like grains in 3-8 µm size from pH 11 plating bath. Identical results from SEM and XRD were obtained from the Cu2O films at longer plating time. After annealing at 350 °C for 30 and 60 min, the Cu2O phase was nicely maintained but SEM images demonstrated coarser grains. Photoelectrochemical activity for H2 generation was obtained on the Cu2O films before and after annealing by recording relevant photoelectrochemical currents at − 0.3 V in 0.5 M aqueous Na2SO4 solution. For the Cu2O films from both baths, substantial increments in photoelectrochemical current were observed for the annealed samples as opposed to as-deposited ones. The largest photoelectrochemical current was obtained at 0.143 mA/cm2 from the Cu2O film of pH 9 plating bath with 60 min annealing, which exhibited a 560% increase over the as-deposited sample. We attributed the enhanced photoelectrochemical current to the improved crystallinity and reduced defects for the annealed Cu2O films. 相似文献
2.
Cu2O thin films were first deposited using magnetron sputtering at 200 °C. The samples produced were then annealed by a rapid thermal annealing (RTA) system at 550 °C in a protective atmosphere with or without the addition of oxygen. After annealing, various Cu2O and CuO films were formed. These films were characterized, as a function of oxygen concentration in RTA, using UV-VIS photometer, four-point probe, and Hall measurement system. The results show that these Cu2O thin films annealed at 550 °C with more than 1.2% oxygen added in the protective argon atmosphere would transform into the CuO phase. Apparently, the results of RTA are sensitive to the amount of oxygen added in the protective atmosphere. The resistivity of these Cu2O thin films decreases with the increase in the oxygen amount in the annealing atmosphere, most likely due to the increase in carrier mobility. In addition, Cu2O/ZnO (doped with AlSc) junctions were produced at 200 °C and annealed. The rectifying effect of P-N junction disappeared after annealing, probably due to the damage of p-n interface, which directly causes current leakage at the junction. 相似文献
3.
Cu2O-Ag thin films were co-deposited by reactive sputtering on glass substrates. During deposition, Ag contents and deposited temperatures were varied. After deposition, a UV-VIS-NIR photometer and a Hall measurement system were used to characterize the optical and electrical properties of these films. The results showed that the Cu2O-Ag thin films had a decreased optical transmittance with the increase of Ag contents. The resistivity was also decreased, which is most likely due to the formation of Ag phase. Through the measurement of photo-induced conductivity, it was found that, when Ag concentration was at 4 at.%, the film had the highest increase in conductivity under light irradiation. This is due to the co-existence of Ag2O and Cu2O. However, when deposited at a temperature higher than room temperature, the photo-induced conductivity of this film became less obvious, apparently due to the dissociation of Ag2O. The results of Photoluminescence (PL) measurement confirmed that the Cu2O-Ag(4 at.%) sample might produce more electron-hole pairs than other samples, which caused the increase of conductivity. 相似文献
4.
80 nm-thick Ni50Fe50 layers were sputter-deposited on glass substrates at 400 °C and then Au layers were sputter-deposited on the Ni50Fe50 layers. The Au/Ni50Fe50 bilayer films were annealed in a vacuum of 5×10−4 Pa from 250 to 450 °C for 30 min or 90 min. The characteristics of the Au layers were studied by Auger electron spectroscopy, field emission scanning electron microscopy, X-ray diffraction and a four-point probe technique. When the annealing temperature reaches 450 °C, Fe and Ni atoms diffuse markedly into the Au layer and the Fe content is more than the Ni content. When the annealing temperature is lower than 450 °C, the grain size of the Au layers does not change markedly with annealing temperature. However, as the annealing temperature reaches 450 °C, the annealing promotes the grain growth of the Au layer. As the annealing temperature exceeds 300 °C, the resistivity of the bilayer films increases with increasing annealing temperature. The diffusion of Fe and Ni atoms into the Au layer results in an increase in the resistivity of the annealed bilayer film. Large numbers of Fe and Ni atoms diffusing into the Au layer of the annealed Au/Ni50Fe50 bilayer film lead to a significant decrease in the lattice constant of the Au layer. 相似文献
5.
RuO2-SiO2 thin films with different Si/Ru molar ratios were prepared by the sol-gel method, using the hydrate ruthenium (III) chloride (RuCl3·3.5H2O) and tetraethylorthosilicate as precursors. The crystal structure, resistivity, chemical bonding configuration, transmittance, carrier concentration, and mobility of the RuO2-SiO2 films were investigated before and after annealing in N2 ambient at 400-700 °C. The resistivity of the RuO2-SiO2 films with different Si/Ru molar ratios decreased abruptly after annealing at 400-700 °C. On the other hand, RuO2 phase precipitated in the RuO2-SiO2 films with different Si/Ru molar ratios after annealing. Fourier transform infrared spectroscopy spectra indicated that the water absorption occurs for as-deposited RuO2-SiO2 films with different Si/Ru molar ratios. The transmittance of all RuO2-SiO2 films presented transmittance maximums after annealing at 700 °C. The carrier concentration and mobility of RuO2-SiO2 films are related to the Si/Ru molar ratios and the annealing temperature. This study discusses the connection among the material properties of the RuO2-SiO2 films and how they are influenced by the Si/Ru molar ratios and the annealing temperatures of RuO2-SiO2 films. 相似文献
6.
Cu2SnSe3 thin films were prepared by single-step D.C. sputtering at 100-400 °C for 3 h using targets composed of Cu2Se and SnSe2 in three different ratios of 2/1 (target A), 1.8/1 (target B), and 1.6/1 (target C). The advantages of self-synthesized SnSe2 instead of commercially available SnSe for depositing Cu2SnSe3 thin films were demonstrated. Effects of target composition and substrate temperature on the properties of Cu2SnSe3 thin films were investigated. Structure, surface morphology, composition, electrical and optical properties at different process conditions were measured. The 400 °C-sputtered films obtained from target B display with direct band gap of 0.76 eV, electrical resistivity of 0.12 Ω cm, absorption coefficient of 104-105 cm− 1, carrier concentration of ∼ 1.8 × 1019 cm− 3, and electrical mobility of 2.9 cm2/V s. 相似文献
7.
Cubic MgxZn1−xO thin films with Mg composition around 70% were deposited on A-plane and M-plane sapphire substrates by rf-reactive magnetron sputtering. Measured structural and optical properties of these thin films indicated an optimal annealing temperature of 700 °C which produced high quality cubic MgZnO thin films on both substrates. Moreover, when the annealing temperature exceeded 750 °C, a much rougher surface resulted, and several large mosaic particles on the surface of the annealed films appeared. From EDX results, the Mg composition was lower than that found in other sections of the annealed films. We attributed this to thermally induced reconstruction of the crystallites. This phenomenon was more obvious for annealed MgZnO films on A-plane sapphire than that on M-plane sapphire. Thermal expansion mismatch with the substrate is the principal reason. 相似文献
8.
Sb2Te3 films of different thicknesses, in the thickness range 300-620 nm, were prepared by thermal evaporation. X-ray analysis showed that the as-deposited Sb2Te3 films are amorphous while the source powder and annealed films showed a polycrystalline nature. The AC conductivity and dielectric properties of Sb2Te3 films have been investigated in the frequency range 0.4-100 kHz and temperature range 303-373 K. The AC conductivity σAC(ω) was found to obey the power law ωs where s?1 independent of film thickness. The temperature dependence of both AC conductivity and the exponent s can be reasonably well interpreted by the correlated barrier hopping (CBH) model. The experimental results of the dielectric constant ε1 and the dielectric loss ε2 are frequency and temperature dependent and thickness independent. The maximum barrier height WM calculated from dielectric measurements according to the Guintini equation agrees with that proposed by the theory of hopping of charge carriers over a potential barrier as suggested by Elliott for chalcogenide glasses. The effect of annealing at different temperatures on the AC conductivity and dielectric properties was also investigated. Values of σAC, ε1 and ε2 were found to increase with annealing treatment due to the increase of the degree of ordering of the investigated films. The Cole-Cole plots for the as-deposited and annealed Sb2Te3 films have been used to determined the molecular relaxation time τ. The temperature dependence of τ indicates a thermally activated process. 相似文献
9.
10.
Indium sulfide thin films prepared using spray pyrolysis, with In/S ratio 2/3 in the solution, were annealed in vacuum at 300 and 400 °C. The effect of this treatment on properties of the films was studied using X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, optical absorption, transmission and electrical measurements. Optical constants of the films were calculated using the envelope method. Annealing did not affect the optical properties of the film much, but the resistivity of the films showed a drastic decrease and the grain size increased. In2S3 thin films have potential use as buffer layer in photovoltaic heterojunction devices. 相似文献
11.
The influence of SiO2 layer thickness of (Fe52Pt48)88Cu12:SiO2 multilayer nanocomposite films on their structural and magnetic properties were investigated. The films were deposited on (001) textured FePt films, and then annealed at 873 K. The crystalline texture of (Fe52Pt48)88Cu12:SiO2 films changes drastically with respect to the thickness of the SiO2 layers. In the film with 50-Å thick SiO2 layers, the (111) peak was strong although the (001) orientation is dominant, and self-organized spherical FePtCu particles were formed in the SiO2 matrix. However, in the film with 19-Å thick SiO2 layers, flat FePt grains with perfect (001) orientation were obtained. In addition, twins with different crystalline orientations were seen in the above films with different thicknesses of the SiO2 layers. Accordingly, different perpendicular hysteresis loops were obtained. 相似文献
12.
Cu2O cubes with average edge lengths of 640 nm were prepared by a chemical reduction approach. The as-synthesized Cu2O particles were deposited on carbon clothes for electrochemical characterizations in cyclic voltammetry (CV) and potentiostatic measurements. In 0.5 M NaOH electrolytes saturated with N2 or CO2, both the Cu2O and carbon clothes were stable at the potential range of 0 to − 1.7 V. Comparisons in the current responses from the CV and potentiostatic measurements suggested the Cu2O with notable catalytic abilities for the CO2 reduction. The mass activity was estimated at 0.94 mA/mg. Chemical analysis from gas chromatography confirmed the methanol to be the predominant product. 相似文献
13.
Xiaoyong Gao Mengke ZhaoZengyuan Zhang Chao ChenJiaomin Ma Jingxiao Lu 《Thin solid films》2011,519(19):6620-6623
Single-phased and (111)-oriented Ag2O film deposited using direct-current reactive magnetron sputtering is annealed using different annealing temperatures (Ta) for 1 h in Ar and H2 mixture. After hydrogen annealing, a very weak but clear Ag(200) diffraction peak begins to appear, and the Ag2O diffraction peak weakens at Ta = 175 °C. However, the Ag diffraction peak becomes discernable at Ta = 190 °C. No Ag2O diffraction peaks but rather Ag diffraction peaks are discerned at Ta = 200 °C. The hydrogen reduction effect can reduce the film's critical thermal decomposition temperature to 175 °C. After hydrogen annealing, the surface of the film evolutes from compact and uniform to osteoporosis, and then to a porous structure. Moreover, the optical properties of the film obviously change at Ta over 190 °C, indicating that the hydrogen reduction can significantly enhance the decomposition of Ag2O due to H2 dissociation on the surface followed by gaseous H2O molecule formation and desorption. 相似文献
14.
Transparent semiconductor thin films of Zn1 − xTixO (0 ≦ x ≦ 0.12) were deposited on alkali-free glass substrates by the sol-gel method. The effects of Ti addition on the crystallization, microstructure, optical properties and resistivity of ZnO thin films were investigated. The as-coated films were preheated at 300 °C, and then annealed at 500 °C in air ambiance. X-ray diffraction results showed all polycrystalline Zn1 − xTixO thin films with preferred orientation along the (002) plane. Ti incorporated within the ZnO thin films not only decreased surface roughness but also increased optical transmittance and electrical resistivity. In the present study, the Zn0.88Ti0.12O film exhibited the best properties, namely an average transmittance of 91.0% (an increase of ~ 12% over the pure ZnO film) and an RMS roughness value of 1.04 nm. 相似文献
15.
The degradation of epitaxial thin films of YBa2Cu3O7 has been studied as a function of annealing temperature in air and in vacuum; some samples had an evaporated overlayer of CaF2. Degradation was monitored by the measurement of electrical properties after consecutive 30-min annealing treatments. The room-temperature resistance registered significant increases for all samples after annealing at temperatures above about 200°C; the critical current density at 77 K was degraded for annealing temperatures 400°C in air, and 200–250°C in vacuum. By annealing in oxygen at 550°C, electrical properties were restored in degraded bare YBCO samples annealed in vacuum, but not for those annealed in air. 相似文献
16.
Multi-stage evaporation is a well-established method for the controlled growth of chalcopyrite thin films. To apply this technique to the deposition of Cu2ZnSnS4 thin films we investigated two different stage sequences: (A) using Cu2SnS3 as precursor to react with Zn-S and (B) using ZnS as precursor to react with Cu-Sn-S. Both Cu2SnS3 and ZnS are structurally related to Cu2ZnSnS4. In case (A) the formation of copper tin sulphide in the first stage was realized by depositing Mo/SnSx/CuS (1 < x < 2) and subsequent annealing. In the second stage ZnS was evaporated in excess at different substrate temperatures. We assign a significant drop of ZnS incorporation at elevated temperatures to a decrease of ZnS surface adhesion, which indicates a self-limited process with solely reactive adsorption of ZnS at high temperatures. In case (B) firstly ZnS was deposited at a substrate temperature of 150 °C. In the second stage Cu, Sn and S were evaporated simultaneously at varying substrate temperatures. At temperatures above 400 °C we find a strong decrease of Sn-incorporation and also a Zn-loss in the layers. The re-evaporation of elemental Zn has to be assumed. XRD measurements after KCN-etch on the layers prepared at 380 °C show for both sample types clearly kesterite, though an additional share of ZnS and Cu2SnS3 can not be excluded. SEM micrographs reveal that films of sample type B are denser and have larger crystallites than for sample type A, where the porous morphology of the tin sulphide precursor is still observable. Solar cells of these absorbers reached conversion efficiencies of 1.1% and open circuit voltages of up to 500 mV. 相似文献
17.
Lead germanate-silicate (Pb5Ge2.85Si0.15O11) ferroelectric thin films were successfully fabricated on Pt/Ti/SiO2/(100)Si substrates by the sol-gel process. The thin films were fabricated by multi-coating at preheating temperatures of 350 and 450 °C. After annealing the thin films at 600 °C, the films exhibited c-axis preferred orientation. The degree of c-axis preferred orientation of the thin films preheated at 350 °C was higher than that of films preheated at 450 °C. Grain growth was influenced by the annealing time. The thin films exhibited a well-saturated ferroelectric P-E hysteresis loop when preheated at 350 °C and annealed at 600 °C for 1.5 h. The values of the remanent polarization (Pr) and the coercive field (Ec) were approximately 2.1 μC/cm2 and 100 kV/cm, respectively. 相似文献
18.
Shufang Wang Liping He Jingchun Chen Mingjing Chen Guangsheng Fu 《Thin solid films》2010,518(23):6829-6832
Epitaxial Bi2Sr2Co2Oy thin films with excellent c-axis and ab-plane alignments have been grown on (001) LaAlO3 substrates by chemical solution deposition using metal acetates as starting materials. Microstructure studies show that the resulting Bi2Sr2Co2Oy films have a well-ordered layer structure with a flat and clear interface with the substrate. Scanning electron microscopy of the films reveals a step-terrace surface structure without any microcracks and pores. At room temperature, the epitaxial Bi2Sr2Co2Oy films exhibit a resistivity of about 2 mΩ cm and a seebeck coefficient of about 115 μV/K comparable to those of single crystals. 相似文献
19.
CuInS2 thin films were deposited by chemical spray of aqueous solutions containing CuCl2, InCl3 and thiourea at substrate temperature of 250 °C in air and subjected to annealing at 530 °C in H2S atmosphere. Structure and composition before and after annealing were studied by XRD, EDS, XPS and Raman spectroscopy. As-sprayed films were low-crystalline, showed uniform distribution of elements in film thickness and no oxygen content. For the CuInS2 films deposited from the solutions with [Cu2+] / [In3+] = 1.0 and 1.1, H2S treatment for 30 min increased the chalcopyrite content up to 73% and 51%, respectively. CuXS phase in sprayed CIS films promotes the crystallite growth but retards the formation of chalcopyrite phase during H2S treatment. 相似文献
20.
Conductive cadmium stannate (Cd2SnO4,) films were grown by a simple spray-pyrolysis technique using aerosols ultrasonically generated from solutions containing Cd(thd)2(TMEDA) and nBu2Sn(AcAc)2, and monoglyme as solvent (thd = 2,2,6,6-tetramethyl-3,5-heptanedionate, TMEDA = N,N,N′,N′-tetramethylethylenediamine, AcAc = acethylacetonate). The overall film growing procedure was carried out at or below 400 °C thus allowing low-melting temperature materials like glass to be used as film substrates. Typical resistivity values of Cd2SnO4 films were found to be ∼ 2 · 10 −3 Ωcm. The films exhibit excellent electrochemical activity with comparable or higher electron transfer rates than cadmium stannate films obtained via sol-gel methods at high annealing temperature. 相似文献