Properties Of Copper Oxide Films Research Articles

Effect of Reactive Magnetron Sputtering Modes (DCMS, HIPIMS, and DC + HIPIMS) on the Properties of Copper Oxide Films

Effect of Reactive Magnetron Sputtering Modes (DCMS, HIPIMS, and DC + HIPIMS) on the Properties of Copper Oxide Films

Ambient Stability of Sodium-Doped Copper Oxide Obtained through Thermal Oxidation.

The ambient stability of copper oxide layers produced through thermal oxidation is a critical factor for their application in advanced photovoltaic devices. This study investigates the long-term stability of thermally grown sodium-doped copper oxides fabricated at 300 °C, 500 °C, and 700 °C. The structural, optical, and electronic properties of these oxide layers were examined after a 30-day period to understand how thermal oxidation temperature and sodium doping influence the durability and properties of copper oxide films. The results indicate that the stability of thermal copper oxide increases with oxidation temperature. The film produced at 700 °C maintained consistent optical properties, work function value, and structural integrity over time, demonstrating their robustness against environmental degradation. In contrast, the layers produced at lower temperatures (300 °C and 500 °C) showed more significant changes due to continued oxidation and adsorption from ambient.

Study of optical and photoelectric properties of copper oxide films

In this work, the dependence of the phase state, photosensitivity region, band structure, and optical quality of 3D-printed nanostructured copper oxide films on the annealing temperature (Ta) was investigated. It was established that both as-deposited and annealed copper oxide films at Ta ≤ 400 °C have the CuO phase and the films annealed at Ta = 450 °C correspond to the Cu2O phase. A possible mechanism of convertation of two phases is discussed. It was established that the band gap of CuO films, caused by indirect allowed optical transitions, determined by the absorption coefficient first derivative and Tauc methods, corresponds to 1.60 eV and 1.35 eV, respectively. It was established that the optical quality of CuO films is the best at Ta = 350 °C. The obtained results open the way to obtain a material suitable for modern optoelectronic applications, in particular, for the development of environmentally friendly solar cells.

Study of optical, structural and electrical properties of copper oxide films prepared by chemical bath deposition with laser at different concentrations

In this study, a copper oxide (CuO) thin film was prepared by the (Continuous-Wave) CW laser assisted-chemical bath deposition (LACBD) technique. The effect of laser wavelength on the structural, optical, and electrical properties of CuO film was investigated. The X-ray diffraction (XRD) study shows that the deposited CuO films are crystalline with a monoclinic structure. The optical energy gap increases with the use of a laser during film preparation and it varies from 2.3 to 1.8 eV. The scanning electron microscope (SEM) images confirm that the morphology of the film was dependent on the laser wavelength. Increasing the laser wavelength results in decreasing the grain size of the film which enhancing the crystallization. Energy dispersive X-ray (EDX) analysis confirms the presence of copper and oxygen elements. Hall measurement revealed that the deposited films are p-type and the electrical conductivity and mobility increased with the use of a laser. The current-voltage characteristics of the p-CuO/p-Si heterojunction were studied in the dark and under illumination. The maximum optical current of the prepared photodetector at a laser wavelength of 550 nm was found to be in the order of 1.59 × 1012 cm.Hz1/2.W-1. The spectral responsivity revealed that the photodetectors exhibit two peaks of response at 450 nm and 800 nm. The maximum responsivity reached was 0.48 A/W at 450 nm and 0.53 A/W at 800 nm for a photodetector prepared at the laser wavelength of 550 nm.

Synthesis and Electrophysical Properties of Copper Oxide Films for Gas Sensors

Thin films of copper oxide were fabricated by sol-gel method. For the preparation of CuO thin films, a sol-gel method based on copper acetate (Cu(CH3COO)2•H2O), isopropyl alcohol (C3H8O) and diethylamine ((CH3CH2 )2NH) was used. The film was applied by centrifugation at a speed of 1500 rpm for 75 seconds. The films were applied in 2, 4, 8 layers with drying between layers for 10 minutes at 250 °C. The thermal probe method was used to determine the p-type of conductivity of the films. The films were annealed at temperatures of 300, 400, 500, 600 °C. By method of X-ray phase analysis, it was found that the main phase in the films is CuO. On films without additional annealing, a single reflex corresponding to CuO (110) 31.7° is observed. After annealing the films at 400 and 500 °C, crystallization occurs and reflexes manifest: (110) by 31.7°, (–111) by 35.5°, (111) by 38.8°, corresponding to CuO. It was found that with an increase in the annealing temperature, the grain size decreases, which indicates the crystallization of the film and contributes to the improvement of gas-sensitive properties. The transparency of the films in the visible range has values T = 30—67 %. The width of the gap is estimated to be 1.9 eV. According to AFM data, the films have a fine-grained structure and with an increase in the annealing temperature from 300 °C to 400 °C, the size of the roughness decreases. The films have high gas sensitivity values (resistance change of 30 %) and low temperature values of maximum gas sensitivity (180—190) °C to ethanol, acetone, ammonia vapors in the air.

The effect of annealing treatment on the structural and optical properties of nanostructured CuxO films obtained by 3D printing

This work studies the effect of post-growth annealing on the structural and optical properties of copper oxide films. Thin films were obtained by 3D printing on glass substrates using ink based on a suspension of CuO nanoparticles. To optimize their structural characteristics and optical quality, the samples were subjected to thermal annealing for 30 min in an argon environment at different temperatures from 250 °C to 500 °C. The obtained samples were studied by scanning electron microscopy, X-ray diffraction, energy dispersive X-Ray, Raman, optical and photoelectric spectroscopy. Based on the obtained results, the main structural and substructural characteristics of the films were established, such as lattice parameters, unit cell volume, texture, sizes of coherent scattering regions, and the level of microdeformation, as well as their dependence on the annealing temperature. In addition, the nature of optical absorption, band gap energies for various types of electronic transitions, and the optical quality of the studied nanostructured copper oxide films were determined. It was shown that CuO films annealed at 350 °C have the best crystalline and optical quality. It was established that at an annealing temperature above 400 °C, a phase transition from the tenorite phase to the cuprite phase is observed. At the same time, a change in the films' substructural characteristics is already observed at Ta = 400 °C. Optimal thermal annealing conditions of CuxO films for effective control of their phase composition have been established.

Study the effect of annealing on the Structural and Optical properties of Copper oxide films prepared by Sol-Gel Spin Coating

This research is to study the effect of annealing on the structural and optical properties on the thin films copper oxide(CuO,Cu2O) was deposited on glass substrate by using technique Spin-Coating (Sol-Gel) with speed (3000 RPM) during the time of the deposition (30 sec). Was the preparation of the solution using a material of copper acetate (Cu(C2H3O2)2.H2O) as a basis and Diethanolamine (DEA) (C4H11NO2) as installed and Ethanol (C2H6O) as a solvent, the solution prepard at a concentration of 0.2M. The annealing at temperatures (250,350, 450,550)°C for one hour. We have investigated the Structural characteristics using (XRD and AFM) analyses ,from of (XRD) analyses show that the thin films are polycrystalline and annealing the films at 350 °C completely converts these films to tenorite structure with composition of CuO. And from (AFM) analyses show that the grian size increases with increasing annealing temperature. Either optical characteristics by spectroscopy UV in the range of wavelength (300-1100) nm. It is observed that the transmittance and allowed direct optical band gap of the films decreases with the increase of annealing temperature from 4.0 eV to 3.92 eV.

Effect of oxygen flow rate ratio on crystalline phase and properties of copper oxide films prepared by room-temperature high-power impulse magnetron sputtering

Copper oxide films were prepared at room temperature using high-power impulse magnetron sputtering (HiPIMS). The oxygen flow rate ratio in the Ar/O2 mixture plasma gas is varied from 1.0% to 3.0% and its influences on the plasma radicals, growth mechanism and film properties are systematically investigated. The crystal phase of the film strongly depends on the oxygen flow rate ratio as indicated by the XRD and XPS results. The films consist of mixed (Cu + Cu2O) phase when deposited with an oxygen flow rate ratio of 1.0–2.5%. The Cu2O fraction increases with oxygen flow rate ratio and reaches the greatest value at 2.5%. A n-type to p-type conductivity transition is observed at around 2.0% due to the increasing Cu2O fraction. A phase transition to CuO is observed at a higher oxygen flow rate ratio of 3.0%. The phase transition and conductivity type transition occurred at a much lower oxygen flow rate ratio but similar O2 partial pressure when compared with those reported in literature, implying that the O2 partial pressure is the critical quantity for reactive sputtering rather than the O2 flow rate ratio. Crucially, the film deposited with 2.5% oxygen flow rate ratio exhibits the highest hole mobility of 32 cm2/V·s, the lowest hole concentration of 4.0 × 1015/cm3, the highest transmittance and the largest band gap of 2.62 eV. The film is potential to be used as the channel material of transparent p-type field effect transistors. The results may be helpful for the preparation of copper oxide film by HiPIMS for application in optoelectronic devices.

The effect of substrate temperature on the physical properties of copper oxide films

The effect of the substrate temperature of the deposition of copper oxide prepared by chemical spray pyrolysis technique was studied. The XRD measurements show that all the films are polycrystalline structure with predominant phase(-111). The crystallite size increase with increasing substrate temperature. The AFM images in 1-D and the 2-D shows that the CuO nanostructure were in the shape of curly sticks growing in a vertical column at an average height of 2.00 nm and an average radius of 40 - 50 nm. These nanostructures of the 3% sample gets higher up to 9.00 nm. The value of the optical energy gap was calculated through the UV-Vis spectrometer and found to decrease with increasing the substrate temperature from 1.93 eV to 1.68 eV. Transmittance values also decreased from 79.5% to 36%.

Structural and magnetic properties of copper oxide films deposited by DC magnetron reactive sputtering

Copper oxide films have been successfully deposited onto glass/Si(100) substrates by DC reactive magnetron sputtering in Ar/O2 gas mixtures, while varying oxygen flow rate. The obtained results based on the structure and magnetic properties are discussed. Depending on the oxygen flow rate, the films reveal different phases and morphologies of Cu2O, Cu4O3 and CuO. In addition, the magnetic properties of the copper oxides thin films are found to be strongly influenced by the oxygen flow rate; the ferro–para transition is influenced by the formation/cancellation of point defects.

CuOX thin films by direct oxidation of Cu films deposited by physical vapor deposition

Thin films of Cu2O and CuO oxides were developed by direct oxidation of physical vapor deposited copper films in an open atmosphere by varying the temperature in the range between 250 and 400 °C. In this work, the influence of oxidation temperature on structural, optical and electrical properties of copper oxide films has been discussed. The characterization results revealed that at lower temperatures (<300 °C), it is feasible to obtained coper (I) oxide whereas at temperatures higher than 300 °C, the copper (II) oxide is formed. The band gap is found to vary in between 1.54 and 2.21 eV depending on the oxidation temperature. Both oxides present p-type electrical conductivity. The carrier concentration has been increased as a function of the oxidation temperature from 1.61 × 1012 at 250 °C to 6.8 × 1012 cm−3 at 400 °C. The mobility has attained its maximum of 34.5 cm2 V−1 s−1 at a temperature of 300 °C, and a minimum of 13.8 cm2 V−1 s−1 for 400 °C. Finally, the resistivity of copper oxide films decreases as a function of oxidation temperature from 5.4 × 106 to 2.4 × 105 Ω-cm at 250 and 400 °C, respectively.

Reactive plasma deposition of high quality single phase CuO thin films suitable for metal oxide solar cells

Copper oxides are of great potential as active optical absorbing materials for low-cost solar cells based on sustainable and green materials resources. In this work, CuO thin films are deposited at room temperature by reactive sputtering deposition using a novel high target utilization system (HiTUS). The films were characterized by X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) analysis, scanning electron microscopy, atomic force microscopy, UV–vis-near infrared absorption spectroscopy, and Hall measurement. The results showed that the deposition rate, phase structures, optical, and electrical properties of copper oxide films were strongly dependent on the sputtering power and the oxygen flow rate. The as-deposited films were characteristically polycrystalline, without evident preference in crystal orientations. This led to highly compact films without the formation of through-thickness columnar grain boundaries typical to conventional reactive magnetron sputtering deposited films. Optical absorption spectroscopy showed that all the CuO films from this work exhibited an indirect optical bandgap about 1.5 eV, without evident effect from the oxygen flow rates. Hall measurement revealed that the CuO films were of p type conductivity, with their hole concentration being readily tunable in a wide range of 1017–1022 cm−3. The ability for refined tuning of the concentration of charged carriers (holes) is critical in realizing the great potential in engineering delivery of CuO photovoltaic (PV) cells with high efficiency.

Effects of molarity on structural, optical, morphological and CO2 gas sensing properties of nanostructured copper oxide films deposited by spray pyrolysis

In this paper, we have exposed the effects of molarity on structural, optical, morphological and gas sensing properties of copper oxide films deposited by pneumatic spray pyrolysis method. The molar concentration was varied from 0.05 to 0.3M. X-ray diffractograms showed the formation of a single phase CuO for films prepared with 0.05 and 0.1M concentrations. A secondary phase Cu2O was obtained for 0.2 and 0.3M concentrations. Optical measurements showed that 0.05M concentration provides a film with the best transparency in the visible and near infrared regions. The thickness values were between 2 and 110µm. Moreover, the contact angle measurements have shown that all the deposited films are hydrophobic with angles between 103° and 121°. The morphological properties were investigated using SEM and AFM. According to SEM and AFM micrographs, 0.05M is the concentration that leads to porous structure. The gas sensing measurements confirm that this porous surface structure is the most sensitive to different CO2 concentrations.

Highly improved hydration level sensing properties of copper oxide films with sodium and potassium doping

In this study, un-doped, Na-doped, and K-doped nanostructured CuO films were successfully synthesized by the successive ionic layer adsorption and reaction (SILAR) technique and then characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and current–voltage (I–V) measurements. Structural properties of the CuO films were affected from doping. The XRD pattern indicates the formation of polycrystalline CuO films with no secondary phases. Furthermore, doping affected the crystal structure of the samples. The optimum conductivity values for both Na and K were obtained at 4M% doping concentrations. The comparative hydration level sensing properties of the un-doped, Na-doped, and K-doped CuO nanoparticles were also investigated. A significant enhancement in hydration level sensing properties was observed for both 4M% Na and K-doped CuO films for all concentration levels. Detailed discussions were reported in the study regarding atomic radii, crystalline structure, and conductivity.

Electrochemical deposition and characterization of cupric oxide thin films

Polycrystalline cupric oxide (CuO) thin films are deposited using an alkaline solution bath employing cathodic electrodeposition method. Thin films are electroplated at various bath temperatures onto conducting indium tin oxide coated glass substrates. The bath temperature effects on the structural, optical and morphological properties of copper oxide films are studied and reported. X-ray diffraction studies revealed mixed phases of monoclinic and cubic for films grown at lower bath temperatures and that the deposited films at temperatures optimized as 75°C exhibited cubic structure with preferential orientation along a (111) plane. Texture coefficient (Tc) values are calculated for all diffraction lines and the films were highly textured (Tc>1). The surface morphology and surface roughness are estimated using scanning electron microscopy and atomic force microscopy, respectively and a morphology made up of pyramid shaped grains is presented. Energy dispersive analysis by X-rays revealed that the near stoichiometric CuO thin films are obtained at optimized preparative parameters. The refractive index is calculated using the envelop method. Also, the optical constants of CuO thin films such as complex dielectric constant (ε) and extinction coefficient (k) are also evaluated and reported.

Some physical properties of In doped copper oxide films produced by ultrasonic spray pyrolysis

In this work, we have reported the effect of In doping on structural, optical and surface properties of copper oxide films obtained by a low-cost ultrasonic spray pyrolysis technique. Thicknesses, refractive indices and extinction coefficients of the films have been determined by Spectroscopic ellipsometry technique using Cauchy-Urbach model for fitting. A very good agreement was found between experimental and theoretical parameters with low MSE values. Transmission and reflectance spectra have been taken by UV Spectrophotometer, and band gap values have been determined by optical method. Structural properties of the films were investigated with X-ray diffraction patterns. In doping caused the films to growth through some certain directions. Atomic force microscope images have been taken to see the effect of In doping on surface topography and roughness of copper oxide films. Surface properties of undoped films have been improved by In doping. Lowest roughness values have been obtained for In doping at 1%. As a result, we have concluded that properties of copper oxide films which are commonly used in solar cells may have improved by In doping (especially In doped at 1%).

Preparation of nanocrystalline Cu2O thin film by pulsed laser deposition

In this paper, the synthesis of nanocrystalline copper oxides Cu2O and CuO thin films on glass substrates using a pulsed 532 nm Nd:YAG laser is presented. Deposition of films is achieved at two different substrate temperatures. The influence of substrate temperature on the structural and optical properties of copper oxide films are discussed and analyzed. The X-ray diffraction (XRD) results show that the deposited films are crystalline in nature. Films prepared at 300 °C substrate temperature were Cu2O and has (111) and (200) diffracted peaks, while films grown at 500 °C were CuO and has (111) and (020) planes. The morphology of deposited films were characterized by scanning electron microscope (SEM) and atomic force microscope (AFM). The optical energy gap of Cu2O and CuO films have been determined and found to be 2.04 and 1.35 eV respectively.

Fabrication of cuprous and cupric oxide thin films by heat treatment

Cuprous oxide (Cu 2O) and cupric oxide (CuO) thin films were prepared by thermal oxidation of copper films coated on indium tin oxide (ITO) glass and non-alkaline glass substrates. The formation of Cu 2O and CuO was controlled by varying oxidation conditions such as, oxygen partial pressure, heat treatment temperature, and oxidation time. The microstructure, crystal direction, and optical properties of copper oxide films were measured with X-ray diffraction, atomic force microscopy, and optical spectroscopy. The results indicated that the phase-pure Cu 2O and CuO films were produced in the oxidation process. Optical transmittance and reflectance spectra of Cu 2O and CuO clearly exhibited distinct characteristics related to their phases. The electrical properties indicated that these films formed ohmic contacts with Cu and ITO electrode materials. Multilayers of Cu 2O/CuO were fabricated by choosing the oxidation sequence. The experimental results in this paper suggest that the thermal oxidation method can be employed to fabricate device quality Cu 2O and CuO films that are up to 200–300 nm thick.

Controlled growth and characteristics of single-phase Cu 2O and CuO films by pulsed laser deposition

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.

Some physical properties of copper oxide films: The effect of substrate temperature

In this work, copper oxide films were deposited at different substrate temperatures of 200, 250, 300 and 350 ± 5 °C by ultrasonic spray pyrolysis technique and the effect of substrate temperature on the structural, surface, optical and electrical properties of the films was presented. The film structures were studied by X-ray diffraction (XRD). To obtain information about structural properties in detail, the grain size ( D), dislocation density ( δ) and lattice parameters ( a = b = c for cubic structure) for preferential orientations were calculated. The surface properties and elemental analyses were characterised using scanning electron microscopy and energy dispersive X-ray spectroscopy, respectively. Optical properties of the films were analyzed by transmission, linear absorption coefficient and reflection spectra, and the optical method was used to determine the band gaps of the films. The current–voltage values were measured with two-probe technique, and the electrical conductivities were calculated. Consequently, it was determined that substrate temperature has a strong effect on the structural, surface, optical and electrical properties of copper oxide films.