Doped CuO Thin Films Research Articles

Enhanced Opto-electronic Properties of Nd Doped CuO Thin Film

Here, pure, and Nd-doped CuO thin films with different composition (0.5 mol%, 1 mol%, 3 mol% and 5 mol%) were prepared following sol-gel spin coating route. X-ray diffraction analysis exhibited polycrystalline monoclinic structure of the films. Crystallite size and micro-strain were calculated from XRD analysis. As Nd doping was increased, crystallite size decreased for any addition beyond 0.5 mol%. Micro-Strain was also increased with increasing Nd doping indicating the lattice misfit because of size difference of Cu2+ and Nd3+. Optical properties of the pristine and Nd doped films were characterized using UV-visible spectrophotometry. The bandgap values were 1.92, 1.90, 1.87, 2.02 and 1.97eV for undoped, 0.5 mol%, 1mol%, 3 mol% and 5 mol% Nd doped films, respectively. Various optical parameters and dielectric constants were calculated for various optoelectronic applications. The topography of the films was studied using Atomic Force Microscopy and it revealed that the average roughness of the films varied in the range of 4.9 to 8.1nm. Electrical conductivity of the undoped film was increased from 0.315 to 0.596 Scm-1 for 5 mol% Nd doping which was measured using a 4-point probe method. Hall measurements showed an increment of carrier concentration by an order of 10 for the 5 mol % Nd doping compared to undoped CuO thin film, where charge carrier mobility was also increased from 0.102 to 0.453 cm2V-1s-1. However, for the maximum doping concentration of 5 mol%, the films remained p-type semiconductor confirmed by the positive value of the co-efficient RH.

Experimental and Theoretical Investigation of Zr‐Doped CuO/Si Solar Cell

Copper oxide (CuO) is a nanostructured semiconductor material with the potential for solar energy conversion and can be suitable for solar cells when used as a thin film. Herein, nondoped and doped (doping ratios of 1%, 2%, and 3% zirconium [Zr]) CuO thin films on silicon (Si) with the spin‐coating technique are developed. Optical and topological characterizations of CuO thin films are examined by ultraviolet‐visible and X‐ray diffraction. The electrical properties of nondoped and Zr‐doped CuO/Si heterojunctions are investigated with experimental current–voltage measurements in the dark and under illuminated conditions. The electrical behavior of nondoped and Zr‐doped CuO/Si heterojunctions is obtained using the experimental J–V technique and computational Cheung–Cheung and Norde methods. A simulation based on nondoped and Zr‐doped CuO/n‐Si heterojunction solar cells using SCAPS‐1D is completed. Photovoltaic (PV) parameters of experimentally produced and theoretically calculated CuO and Zr‐doped CuO/Si heterojunction solar cells are compared. Accordingly, PV parameters of 1% Zr‐doped CuO/Si solar cells show the highest power conversion efficiency calculated as a function of interfacial defect density and hole carrier concentration.

Electrical, optical and nonlinear optical process in spray pyrolyzed Zn:CuO nanostructures for optoelectronic device applications

Nanostructured pure and Zn doped CuO thin films were deposited on a glass substrate at 400 °C using the chemical spray pyrolysis method. The fabricated thin films were characterized to study the compositional, structural, morphological, optical and electrical properties. X-ray diffraction spectra show the polycrystalline nature of the sample and confirm the monoclinic phase of copper oxide. Raman analysis further confirms the absence of cuprous oxide phases and impurities. High absorbance in the visible region was observed for the films with bandgap values ranging from 1.7–2.0 eV. A near-band edge emission peak in the red region is recorded in the photoluminescence spectra. Uniformly distributed nanoparticles are observed in SEM images. Hall effect measurements indicate p-type conductivity and 5% Zn doped copper oxide showed the highest conductivity and carrier concentration. The non-linear absorption coefficient (β eff) of the samples was obtained with the help of z-scan method with a Helium-Neon laser under the CW regime. Zn doping results in an increase in nonlinear absorption, supporting the use of Zn:CuO for optoelectronic devices.

SIMULATION STUDIES OF CR DOPED CUO HETEROJUNCTION SOLAR CELL

1% and 3% Cr doped CuO thin films have been deposited on soda lime glass by spin coating method and then their structural, morphological and optical properties have been investigated by operating X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Ultraviolet-Visible Spectroscopy (UV-Vis) techniques, respectively. XRD patterns of CuO:Cr (1%) and CuO:Cr (3%) thin films demonstrate characteristics of monoclinic CuO structure with a C2/c space group. The morphology of coated film plays an important role in analyzing some optoelectronic properties. 1% Cr doped CuO thin film absorbs more photons compared to 3% Cr doped CuO in Vis and UV regions. The band gaps of 1% Cr and 3% Cr doped CuO thin films are to be 2.18 eV and 2.30 eV, respectively. The Mo/1% and 3% Cr doped CuO/n-ZnO/i-ZnO/AZO solar cell has modelled with SCAPS-1D simulation program. The photovoltaic (PV) parameters of solar cell deteriorated with some increase in the neutral defect density (N_t) value. As the shallow acceptor defect density (N_a) value is increased, J_SC is decreased, V_OC, FF and η are increased. PV performance of 1% Cr doped CuO solar cell were found to be better than that of 3% Cr doped CuO solar cell. The efficiency of 1% Cr doped CuO solar cell is increased with the use of SnO2 intermediate layer in 2 nm thickness at the heterojunction interface.

Sputtered nanocrystalline samarium doped CuO photoelectrode for efficient photoelectrochemical water splitting

Copper oxide (CuO) is a promising photoelectrode for photoelectrochemical (PEC) energy generation because of its fascinating properties, including high earth availability and inexpensive. In this context, samarium (Sm)-doped CuO thin films are deposited on a glass substrate through the sputtering technique to serve as photocatalysts in PEC water splitting. The structural characterizations of sputtered films were performed with X-ray diffraction (XRD) spectroscopy, while the morphology and elemental composition of all films were studied with the help of field-emission scanning electron microscopy (FE-SEM) connected with a dispersive energy X-ray analyzer. XRD pattern has shown that all films are polycrystalline with a preferred orientation of (−111) crystallographic plane. FE-SEM images and ImageJ analysis showed that all deposited particles are uniformly distributed as disassembled particles over the substrate area. The optical energy band gap (Eg) was increased by adding the Sm contents in the CuO films. The photocurrent density for the photoelectrode was improved by Sm dopants as compared to the pure sample and recorded its maximum value of − 4.66 mA/cm2 at ∼ − 0.385 V vs. RHE which was about 4 times higher than that of the pure sample with feasible photostability retention. Additionally, the value of the charge transfer resistor for the CuO photocathode with the smallest amount of Sm ions was the lowest as compared to other photocathodes. These results offer a practical method for creating a brand-new fabrication technique for PEC devices with remarkable water-splitting efficiency.

Fabrication of Polyvinyl Alcohol Doped CuO Thin Films for Improved Amperometric-Non Enzymatic Hydrogen Peroxide Sensing

Fabrication of Polyvinyl Alcohol Doped CuO Thin Films for Improved Amperometric-Non Enzymatic Hydrogen Peroxide Sensing

Efficient room temperature carbon dioxide gas sensor based on barium doped CuO thin films

For a safe environment, harmful-gas sensors of low cost and high performance are essential. For CO2 gas sensing applications, Ba-doped CuO thin films with 4 mol% and 6 mol% Ba were produced on glass substrates using the successive ionic layer adsorption and reaction approach. Utilizing various techniques, crystallographic structures, nanomorphologies, and elemental compositions were examined to assess the impact of doping on the characteristics of the films. According to the structural and morphological analyses, the nanocrystalline films consisted of irregularly shaped nanoparticles, which assembled to form a rough surface with unequal grain sizes. Because of its nanoporous nature, the CuO:6% Ba thin film exhibited the most substantial nanomorphological change and the highest gas sensing capability. At varied CO2 gas flow rates, the maximum sensor response (9.4%) and Rair/RCO2 ratio (1.12) at room temperature (RT = 30 °C) were observed at 100 SCCM. By optimizing the sensor’s operating temperature, the sensor response value reached 82.2% at 150 °C, which is approximately eight times the value at RT. Selectivity, reusability, repeatability, detection limit, and quantification limit were all tested. It shows excellent response and recovery times of 5.6 and 5.44 s. In comparison to prior literature, the improved sensor is suited for use in industrial applications.Graphical abstract

Structural, optical, and H2 gas sensing analyses of Cr doped CuO thin films grown by ultrasonic spray pyrolysis

Here, a specific metal oxide (CuO) and its impurity (Cr) added composites were grown onto glass substrates as nanostructured thin films by executing ultrasonic spray pyrolysis method. The effects of the varied Cr dopant concentration on the morphological, structural, optical and H2 gas sensor properties of the synthesized CuO thin films were determined by conducting scanning electron microscopy, X-ray Diffraction, X-ray photoelectron spectroscopy, photoluminescence spectroscopy, ultraviolet–visible spectroscopy, and gas detection analyses. The X-Ray Diffraction analysis revealed the presence of CuO crystals with predominant (111) plane and it changed to (002) orientation for the doped samples, where crystallite sizes varied between 32 and 46 nm. The structural studies disclosed that the crystalline structure modified due to the added impurities. The scanning electron microscopy observations unveiled polyhedron-like shape formations of the synthesized nanostructures which also showed clear indications of changed morphology due to the impacts of different Cr doping percentages. Besides, the presence of copper, oxygen, and chromium was confirmed by EDX elemental analysis as well as X-ray photoelectron spectroscopy. The optical examination concluded that absorbance values followed a random trend with respect to the increased impurity contents while bandgap decreased with the increase of doping concentration. And, it was also noted that the luminescent emission peaks decreased in the photoluminescence spectroscopy as a result of introduced impurity levels. Finally, H2 responsivity was detected for the grown films and found out that the impurity doping notably increased the sensitivity of the gas sensor based on the prepared CuO nanostructures.

Pb-Doped CuO Thin Films Synthetized by Sol-Gel Method

Abstract The physical properties of pure CuO and Pb doped CuO thin films, deposited on glass substrates by a sol-gel method, were investigated. Structural analysis revealed the polycrystalline nature of the pure CuO and Pb:CuO composite films with a monoclinic structure, the crystallite size decreased and ranged from 36.78 nm to around 21.5 nm. The SEM images of the CuO thin films showed that the Pb doping concentration affects the surface morphology of the Pb:CuO composites. The absorbance of the Pb:CuO composites is higher than that of the undoped CuO thin films. The optical band gap energies of undoped CuO and Pb doped CuO thin films were estimated to 1.9 (pure), 2.17(5%) and 2.74 (7%)eV, and found that the band gap energy (Eg) increases with the Pb concentration. This blue shift is due to the quantum confinement induced by the reduction in the size of the crystallites.

SILAR processing and characterization of bare and graphene oxide (GO) and reduced graphene oxide (rGO)-doped CuO thin films

SILAR processing and characterization of bare and graphene oxide (GO) and reduced graphene oxide (rGO)-doped CuO thin films

Enhanced opto-electronic properties of X-doped (X = Al, Ga, and In) CuO thin films for photodetector applications

Recent trends in optoelectronics still need a highly efficient photodetector based on p-type metal oxide semiconductors. This work stands with the improvement in the performance of CuO thin films via doping with different metals into the thin films. The CuO thin films were successfully doped with 1 wt% of X (X = Al, Ga, and In) by spray pyrolysis method. The prepared doped CuO thin films were characterized to interpret the structural, morphological, and elemental characteristics using advanced techniques. These doped CuO thin films were subjected to study the photodetection ability by analyzing optoelectronic properties. The doping also tuned the optical and electrical properties. Among the fabricated photodetectors, the Al-doped CuO detector shows a maximum photocurrent. The CuO:Al (1.0%) thin film exhibits a high photocurrent of 2.59 × 10−6 A, the responsivity of 2.82 × 10− 1 AW− 1, the external quantum efficiency of 66%, and the detectivity of 1.45 × 1010 Jones. Compared to the other thin films, Al doping has remarkably reduced the bandgap and shows a good photosensing activity that may be due to an increase in charge carriers. These outcomes provide a way to assemble good photodetectors and tune their properties in a wide range.

Investigating the effect of La doped CuO thin film as absorber material for solar cell application

The main objective of the study is to analyze the properties of undoped and La doped CuO (LCO) thin films as potential absorber for photovoltaic application. Chemical spray pyrolysis technique has been used to prepare the undoped and LCO thin films with different wt% (2, 4, 6, 8 and 10). All the films exhibit polycrystalline monoclinic crystal structure and no peaks related to impurity phases are identified. The average crystallite size of the La doped films is decreased from 19.51 nm to 8.73 nm. From UV spectra, the La doped films exhibit high optical absorption and their band gap value decreases from 1.62 eV to 1.49 eV upto 6 wt%. The PL intensity of the CuO films decreases upto 6 wt% of La and then increases. The SEM image of La doped films show the uniform, homogenous and compact surface with decrease in grain size. From Hall measurement, the 6 wt% of LCO shows higher carrier concentration (4.68 × 1019 cm−3) and lower electrical resistivity (1.33 Ω cm). All the films exhibit ohmic behavior and 6 wt% of La shows higher dark current (1.41 mA) and photoresponse of 1.5 mA. The photovoltaic performance of undoped and 6 wt% of LCO solar cells is evaluated, and their power conversion efficiencies are 0.34% and 1.36% respectively. The above mentioned results determined that 6 wt% of LCO thin films can be used as an effective absorber material for solid state p-n junction solar cell.

Fabrication of Er, Tb doped CuO thin films using nebulizer spray pyrolysis technique for photosensing applications

CuO-based high-performance photo-sensors are a key area of research and challenge in today's scenario. In view of this, we study undoped, CuO:Er (1%),CuO:Tb (1%), and Er(1%),Tb(1%) dual doped CuO thin films for photodetector applications using the nebulizer spray pyrolysis technique. The structural, morphological, and optical features of the coated samples were systematically studied using few techniques such as X-ray diffraction (XRD), Scanning electron microscope (SEM), UV–Vis spectra, Photoluminescence (PL) and two probes. According to the XRD analysis, all the doped thin films show a good crystalline structure with a predominant peak exhibition (002) plane and the doping process enlarged the crystallite size value and obtained a maximum of 44 nm for Er,Tb dual doped CuO film. SEM photo shows the formation of a flaky nanoparticle structure. In the case of light absorption, the absorption level depends on dopant materials such as Er and Tb and the UV absorption level is improved for the dual doped film. The photo-luminescence shows that all the prepared samples exhibit defect-related peaks around 412, 450, 475, 525 nm and the doping process significantly improves the luminescence properties of CuO films. According to Hall effect analysis all prepared samples show the p-type characteristics whose film resistance and mobility are increased and the highest value is noted for Er(1%),Tb(1%) doped CuO thin film. The photo-detection capacity was studied by the analysis of optoelectronic properties for these doped CuO thin films. The UV sensing study indicates, high responsivity (4.85⨯10−1AW−1), external quantum efficiency (113%), and detectivity (1.89⨯1010 Jones) values for the Er, Tb dual doped CuO photodetector. The work also discusses a possible mechanism of ultraviolet photo-detector performance. These findings share a guideline to develop a high-performance photodetector.

Band gap tuning and p to n-type transition in Mn-doped CuO nanostructured thin films

Here we discuss the synthesis of copper (II) oxide (CuO) and manganese (Mn)-doped CuO thin films varying with 0 to 8 at% Mn using the spray pyrolysis technique. As-deposited film surfaces comprised of agglomerated spherical nanoparticles and a semi-spongy porous structure for 4 at% Mn doping. Energy dispersive analysis of X-rays confirmed the chemical composition of the films. X-ray diffraction spectra showed a polycrystalline monoclinic structure with the predominance of the ( 11) peak. Optical band gap energy for direct and indirect transitions was estimated in the ranges from 2.67–2.90 eV and 0.11–1.73 eV, respectively. Refractive index and static dielectric constants were computed from the optical spectra. Electrical resistivity of CuO and Mn-doped CuO (Mn:CuO) thin films was found in the range from 10.5 to 28.6 Ω·cm. The tiniest electron effective mass was calculated for 4 at% Mn:CuO thin films. P to n-type transition was observed for 4 at% Mn doping in CuO films. Carrier concentration and mobility were found in the orders of 1017 cm–3 and 10–1 cm2/(V·s), respectively. The Hall coefficient was found to be between 9.9 and 29.8 cm3/C. The above results suggest the suitability of Mn:CuO thin films in optoelectronic applications.

Improved photocurrent properties of La doped CuO thin films coated by nebulizer spray pyrolysis method for photosensor applications

In this study, pure and La of various concentrations (0.5, 1.0, 1.5, 2.0, and 2.5 wt.%) doped CuO thin films were produced by means of the NSP technique to be used as UV photodetection applications. Various physicochemical investigations such as XRD, SEM, PL, UV–Vis, and current-voltage (I–V) characteristics have been conducted to inspect the role of La in the grown films. X-ray diffraction data confirm the single cubic crystal structure and the size of crystallites shrinkages from 22.6 to 19.4 nm. SEM photo shows the formation of triangular prismic shape like morphology. The spectroscopic studies show that the added La impurity promotes their absorption level in the UV region and redshift the optical bandgap from 2.07 to 1.81 eV. Photoluminescence spectral analysis confirms the presence of oxygen vacancies at 413 nm. Upon exposure to a UV light source (λ = 365 nm) the fabricated La-doped CuO thin films offered a better photo-responsivity, detectivity, and external quantum efficiency value of 1.63 × 10−1 AW−1, 1.75 × 1010 Jones, and 107% respectively. Our results provide a guideline to design high-performance UV photodetectors.

Structural and optical characterization of nanostructured undoped CuO and cobalt - doped CuO thin films

The undoped CuO and CuO:Co films are grown using spray pyrolysis technique(SPT). The deposited films undergo a clear morphological change due to an increase in Cobalt dopant from 0 to 4 %. The predominant peak was (200) plane has been confirmed by Xray diffraction. Maximum crystalline size was at the (CuO: 4% Co) film, and the strain decreases from 2.98 to 2.59. Study of the morphology specifies the presence of homogeneous grains, these grains were not homogeneous and had different sizes by adding Co atom. AFM images a reduction in roughness from (7.06 to 3.64) nm. The crystallite size was in the area of 41.35 nm to 32.46 nm as calculated by Scherrer’s formula. The average transmittance values for the films were (77, 74 and 71) % for Undoped CuO, CuO: 2% Co and CuO: 4% Co respectively. The optical energy gaps of the films were calculated. the absorption coefficient increased with an increase at 2% or 4% Cobalt dopant, the band gap of Undoped CuO sample was 2.12 eV, and then decreased slightly with Cobalt content to become 2.04 eV for CuO: 2% Co and 2.04 eV for CuO: 4% Co. also The refractive index and extinction coefficient increased via Cobalt contents.

Influence of Ni doping on the morphological, structural, optical and electrical properties of CuO thin films deposited via a spray pyrolysis

Nanostructured copper oxide (CuO) and Nickel (Ni)-doped CuO thin films with different concentrations of Ni ranging from 2 to 8 at.% were synthesized onto a plain glass substrate at the substrate temperature, 350 °C by a thermal spray pyrolysis technique. Field emission scanning electron microscopy (FESEM) analysis of CuO and Ni-doped CuO thin films detected the closely spaced rock-like nanostructures, evenly distributed on the film surfaces. The average particle sizes of CuO and Ni-doped CuO thin films were calculated from the FESEM and found between 260 and 63 nm. Energy-dispersive X-ray analysis revealed that CuO and Ni-doped CuO thin films were stoichiometric and typically comprised of Cu, O, and Ni. X-ray diffraction analysis showed the monoclinic structure of the films with the most preferred orientation plane ( 1 ‾ 11) along with the (111), ( 2 ‾ 02) and (02 2 ‾ ) crystalline planes. The maximum crystallite size was found at about 81 nm for 6 at% Ni-doped CuO thin film. CuO film showed an optical transmittance of about 33% in the visible-NIR region. Ni-doping enhanced the absorbing nature of CuO thin films in the vis-NIR region of light. With the rise of Ni content in CuO thin films, the optical bandgap gradually increased from 2.28 to 2.78 eV. Resistivity raised from 9.28 × 10 3 to 49.01 × 10 3 Ω-cm with the increase of the amount of Ni. • The FESEM micrographs show that the thin film surface of the CuO and nickel (Ni)-doped CuO thin films comprises irregularly shaped nanoparticles that aggregate to form the columnar surface's morphology. • As the Ni increased in the precursor solution for the preparation of Ni-doped CuO thin films, EDX analysis of the prepared films showed an increase in Ni's mass and atomic percentage. • The films' monoclinic structure with the preferred orientation along with the ( 1 ‾ 11) crystalline plane is shown in the X-ray diffraction analysis. • Ni-doping enhanced the absorbing nature of CuO thin films in the vis-NIR region of light. • The optical band gap and electrical resistivity gradually increased with an increase in the CuO thin film's Ni content.

Bond length controlling opto-structural properties of Mn doped CuO thin films: An experimental and theoretical study

In this paper, we present a detailed study of the opto-structural properties of Mn doped CuO (MCO) thin films with 0.0, 2.0, 4.0, 6.0 and 8.0 at.% doping concentrations, using a thermal spray pyrolysis technique as well as Density Functional Theory (DFT) calculations for the first time. The experimental characterizations are done through Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-rays spectroscopy (EDX), X-ray diffraction (XRD), UV–Visible spectroscopy (UV–Vis) and Hall Effect measurement. FESEM images show the petal-like and closed packed flower-like spherical structure surface morphology. EDAX spectra confirm the presence of Cu, O and Mn atoms. The XRD pattern reveals that synthesize thin films have a monoclinic structure with some impurity phases. The estimation of crystallite size ranging from 17.11 to 31.96 nm observed using Debye-Scherrer and Halder-Wagner method. The Cu–O bond length is found consistent between the Rietveld refinement and DFT function, which controls the experimental optical band gap in between 3.00 to 2.31 eV. Further, a standard value of Urbach energy, steepness parameter, electron–phonon interaction, refractive index, dielectric constant and static dielectric constant is found in 4.0 at. % Mn dopant. Moreover, p to n-type conductivity is confirmed by 4.0 at. % Mn concentration. By a meticulous analysis, it is observed that 4.0 at. % of MCO thin films might have a potential application in electronic and optoelectronic device industry.

Optical properties and laser-induced breakdown spectroscopy analysis of Al- or Co-doped CuO thin films prepared on glass by radio-frequency magnetron sputtering

Glasses coated with a variety of thin films are extensively used. In the present study, copper oxide (CuO) thin films doped with aluminum (Al) or cobalt (Co) were prepared on the surface of soda lime glass substrates by radio-frequency magnetron sputtering deposition. The variation of the sputtering time resulted in the alteration of the composition of the films that caused changes in their optical properties as observed by energy dispersive X-ray spectroscopy (EDS) and optical transmission spectroscopy, respectively. In addition, laser-induced breakdown spectroscopy analysis (LIBS) was used to achieve rapid qualitative and quantitative analyses of the doping elements in the CuO thin films. The elemental emission intensity ratios of Al/Cu in CuO-Al thin films and Co/Cu in CuO-Co thin films obtained by LIBS was employed to assess the optical properties of the coated glass samples. Overall, the results revealed that the LIBS technique allows to efficiently determine the elemental composition of doped CuO thin films deposited by RF magnetron sputtering and to simultaneously assess the corresponding optical properties of thin films.

Room temperature gas sensor based on La2O3 doped CuO thin films

In this work, undoped and lanthanum doped cupric oxide (CuO:La) nanorods structured thin films were deposited at different concentrations (CLO) on p-type silicon substrates using the spray pyrolysis technique at 350 °C. XRD, AFM, SEM, and EDX techniques were used to investigate the structural, morphological, and compositional analysis, respectively. A decrease in crystallite size was observed from 13.4 to 7.75 nm and even the peak diffraction intensity decreased with an increase in La concentration. The hexagonal structure of the La2O3 phase with poor orientation planes was observed at 7 wt% La. Amplitude parameters, grain size, and atoms distribution were discussed from AFM analysis. SEM images show a uniform distribution and homogeneous crystalline construction supported by quadrilateral pillars with nanorods-like in shape. The sensitivity, recovery, and response time for CLO thin films as room temperature NO2 sensor devices were calculated. The effect of lanthanum concentration on the sensing mechanism of CuO thin films also has been reported.