Molybdenum Trioxide Thin Films Research Articles

A comprehensive analysis: The effects of 100 MeV Ni7+ ion irradiations on the structural integrity of MoO3 thin films

An effort has been made to comprehensively study the structural modification of the molybdenum trioxide (MoO3) thin film with 100 MeV, Ni7+. The MoO3 nanoparticles were synthesized by hydrothermal method and thin film of MoO3 was fabricated by spin coating technique. MoO3 thin film was subjected to irradiation with 100 MeV, Ni7+ beam with various fluences of 5 × 1012, 1 × 1013, and 3 × 1013 ions cm−2. The structural changes induced by ion beam irradiation were characterized using XRD diffraction, Raman, Fourier Transforms Infrared Spectroscopy (FTIR) UV–visible spectroscopy, and Atomic Force Microscopy (AFM). The synthesized thin film showed an orthorhombic phase and the average crystallite size was 63.8 nm of the pristine sample. it is observed that the crystallinity decreases after irradiation. The Raman study confirmed the XRD findings and also showed that after exposure, intensity of the Raman peaks decreased and the width of the spectra expanded due to a decrement in the crystallinity. The bandgap of the thin films decreased after irradiation as the ion fluence increased up to 3 × 1013 ions cm−2. The findings showed that the ion beam irradiation was directly accountable for the amorphization and lattice defect development in the MoO3 thin films.

Investigation on structural and morphological properties of molybdenum trioxide (MoO3) thin films

Abstract The present study reports on the effect of substrate temperature on structural, morphological and optical properties of MoO3 thin films. MoO3 thin films were deposited on pre-heated glass substrate using spray pyrolysis technique. The substrate temperature was varied from 300 °C to 400°C with a step interval of 50 °C. Structural studies were studied using X-ray diffraction technique. It is observed that all the diffraction peaks exactly match with JCPDS card No. 05-0508. The as –deposited MoO3 thin films exhibits orthorhombic crystal structure. It is found that the crystalline nature increases with the increases of substrate temperature. FESEM micrographs show that the grains are distributed uniformly over the surface without any void. An optical property reveals that the transmission of MoO3 thin film in the visible region increases with increases of deposition temperature.

Investigation of optical properties of molybdenum trioxide (MoO3) thin films using neural networks

Nowadays, transition metal oxide, the semiconductor molybdenum trioxide (MoO3), is a favorable choice because it has several industrial applications and alluring qualities. It has a significant role as an industrial catalyst due to its electrochromic properties. The optical behavior of the MoO3 thin film onto various substrates of the powder of MoO3 was investigated. x-ray diffraction analysis revealed an orthorhombic structure. Measurements of the average crystallite size and dislocation density were obtained, which were 132.8 nm and 5.7× 10–4 nm−2, respectively. Spectrophotometric measurements of transmittance (T) and reflectance (R) at normal incidence in the 300–1400 nm wavelength range of the film onto various substrates were examined. The dispersion and indirect optical transitions and nonlinear optical parameters were identified for glass and quartz substrates. An estimation of the optical behavior of the MoO3 thin film using the artificial neural network (ANN) model was carried out. Experimental data were used as inputs. The optical characterization of ANN modeling outputs provides excellent results. Error values support the success of the modeling process, with a mean squared error value of < 10−1. Moreover, the theoretical equation describing the experimental results was obtained depending on the ANN model, representing the relation between the inputs and outputs. According to the findings of this research, the ANN model can be utilized as an efficient tool to simulate and predict the optical parameters of the MoO3 thin film. Additionally, it can establish strong connections between theoretical and experimental fields.

Improvement in ammonia gas sensing properties of La doped MoO3 thin films fabricated by nebulizer spray pyrolysis method

In the present work, different doping concentration (0, 1, 2, 3, 4 and 5 wt%) of Lanthanum (La) doped Molybdenum trioxide (MoO3) thin films were prepared using low cost Nebulizer spray pyrolysis (NSP)technique. The crystalline, morphology, optical and gas sensing properties of thin films were investigated. The presence of monoclinic MoO3 structure was confirmed through the XRD investigation for all the samples with highest crystallite of 61 nm was observed for 2 wt% La doped MoO3 thin film. The surface morphology of the produced thin films exhibits a reticulate nanofibrous mesh shape with increased particle size and porosity on addition of 2% La dopants in MoO3.The UV–Vis results showed the band gap values for the prepared thin films in the range 3.12–3.26 eV and the minimum bandgap was observed for the 2 wt% of La doped MoO3 thin film. Also the PL results confirmed the presence of more oxygen vacancies for the 2 wt% of La doped MoO3 thin film. The NH3 gas sensing study was conducted for the prepared films at room temperature, the 2 wt% of La doped MoO3thin film exhibits a maximum sensor response of 900, faster response times (28 s and 2.9s) compared to other fabricated devices. The results suggest that the 2% La doping in MoO3 could be an optimum doping concentration for the preparation of commercial NH3 gas sensors.

Impact of thickness on optoelectronic properties of α-MoO3 film photodetectors: Integrating first-principles calculations with experimental analysis

This study focused on investigating the optoelectronic properties of molybdenum trioxide (α-MoO3) thin films using the atomic layer deposition (ALD) technique through different cycle numbers and theoretical investigation. Initial band gap calculations using standard DFT with GGA-PBE resulted in a value of 1.19 eV, which deviated significantly from experimental measurements. The GGA + U method with Hubbard U corrections was applied for the first time to improve the accuracy. This refinement led to a more precise band gap value of 3.09 eV, closely matching previously reported experimental data. The electronic parameters of the α-MoO3 photodetector, such as ideality factor (n), barrier height (Φ0), and series resistance (Rs), were analyzed using the thermionic emission theory and confirmed by Cheung and Nord's methods. The results demonstrated that the sample deposited with 100 pulses exhibited higher photodetector performance under UV illumination, despite having a lower Rs.

Cobalt-doped MoO3 thin films and dual-band electrochromic devices with excellent cyclic stability

Electrochromic (EC) technology has played a pivotal role in elevating the prominence of smart windows by enabling them to alter their color and effectively manage the level of transparency. Nanostructured molybdenum trioxide (MoO3) thin films are highly promising for the development of EC technology. However, the production of uniform, crack-free and durable MoO3 thin films through conventional deposition methods is still a challenge though these properties are critical for achieving prolonged cyclic stability. In this work, we demonstrate the use of ultrasonic spray deposited bare MoO3 and cobalt-doped MoO3 (MoO3:Co) thin films for EC applications. Cobalt (Co) doping is shown to significantly improve the cyclic stability when compared to the bare MoO3 films. Furthermore, MoO3:Co films have exhibited significant performance in novel dual-band electrochromic devices (ECD). After 5000 cycles, the MoO3:Co electrodes showed significantly higher capacitance retention (92%) compared to the bare MoO3 thin film electrodes (54%). Moreover, MoO3:Co electrodes exhibited a higher maximum transmittance change than the bare MoO3 electrodes. Dual-band ECDs showed excellent cycling performance up to 5000 cycles with a capacitance retention of 99%. Obtained results demonstrated the potential of the ultrasonic spray deposition method for MoO3 thin film based EC windows and dual-band ECDs with excellent cyclic stability.

Enhanced sensing properties of Zn-doped MoO3 thin films developed using a nebulizer spray technique

Zn-doped Molybdenum trioxide (MoO3:Zn) thin films were coated on glass substrates using a nebulizer spray pyrolysis technique to apply ammonia (NH3) gas sensing. According to the structure examination, the crystallite size of the as-fabricated thin films is 64–77 nm. Field Emission Scanning Electron Microscopy (FESEM) images of the films confirm the formation of nanograins with islets-like shapes. In addition, Ultraviolet–Visible (UV–Vis) and photoluminescence (PL) studies were used to examine the samples optical bandgap and structural defects. Further, the MoO3: Zn sample's gas-sensing properties for ammonia detection were assessed at ambient temperature. The observed gas response of the MoO3:Zn3% sample was 20,900, and faster response and recovery times of 66s/9s. Furthermore, we observed that the MoO3:Zn3% sensor had exceptional ammonia selectivity.

Highly sensitive pure molybdenum trioxide thin films at a higher annealing temperature for liquefied petroleum gas and humidity sensing at room temperature

Highly sensitive pure molybdenum trioxide thin films at a higher annealing temperature for liquefied petroleum gas and humidity sensing at room temperature

Improvement in ammonia gas sensing properties of Co doped MoO3 thin films prepared by cost effective nebulizer spray pyrolysis method

The capacity to detect and monitor NH3 in the environment in real time has been established using an ammonia (NH3) sensing material consisting of Cobalt (Co) doped Molybdenum trioxide (MoO3) thin films on glass substrates. With Co doping, the XRD peaks of MoO3 films shifted towards lower angle and increase cell volume in the case of 3% Co doped MoO3 film compared to other samples, depicts the successful Co doping into the host structure. The chain link particles observed for as-fabricated MoO3film increased for Co doped films and obtained maximum particle size for 3% Co doped MoO3 film. In addition, to test the films elemental and optical properties, energy-dispersive X-ray (EDX) and UV spectroscopy were used to analyze the prepared samples. Simultaneously, we established the gas-sensing characteristics of Co-doped MoO3 sensors for NH3 detection at room temperature and attained maximum gas response of 9120 % for 3% Co doped MoO3 film. The sensor with 3%Co doped MoO3 sensing film exhibited faster response and recovery times than sensor with undoped MoO3 film, which is critical for MoO3 sensor practical applications. Furthermore, the ammonia selectivity of the doped MoO3 sensors was found to be remarkable.

Effect of low energy nitrogen ion irradiation on MoO3 films

In the present work, Molybdenum trioxide (MoO3) thin films were deposited by the electrophoretic deposition (EPD) method. Low energy ion irradiation was used to alter the materials properties of MoO3 films. Ion irradiation was carried out at a constant ion fluence of 2.16 x 1016 ions/cm2 for energies varying from 10 keV to 40 keV. The X-ray diffraction (XRD) and Raman spectroscopy revealed the orthorhombic α-MoO3 phase. The optical band gap was observed to change from 3.73 eV to 3.08 eV in a controlled manner due to ion irradiation. Morphology of nanobelt-like structures was seen at the highest energy of ion irradiated films. Atomic force microscopy (AFM) revealed a decrease in the surface roughness with an increase in irradiated ion energy. All results are in corroboration with each other and comprehend the process of tailoring the material properties of MoO3 thin film due to low energy ion irradiation. These tailored properties could be useful for electronic or optical device applications.

Amorphous molybdenum trioxide thin films for gas sensing applications

Uniform and smooth substoichiometric Molybdenum trioxide (MoO3−x) films have been achieved via thermal evaporation technique. MoO3 thin films were deposited onto glass and fluorine doped tin oxide (FTO) coated glass slides. The field-emission scanning electron microscopy micrographs reveal the amorphous behavior for films deposited either on glass or FTO substrates. The two thicknesses 500 and 650 nm of MoO3−x films which are deposited on glass and FTO coated glass slides were electrically examined as sensors towards NO,CO2 and HCl gases. The sensing process have been explained based on the electrical dipole layer formation consisting of the two unlike charged ion- layers and causing an energy band bending at the surface region of the film as a result of the gas adsorption. MoO3−x films on glass substrate is a perfect sensor towards oxidizing CO2 and NO gasses. The sensors are very sensitive towards low gas flow rate (20 standard cubic centimeters per minute (sccm)) and manifest the highest sensitivity values at relatively low temperatures compared with the other MOS with short response and recovery times (4 min for CO2 and 2 min for NO). The recorded sensitivity of MoO3−x sensor towards CO2 and NO gases at temperature 200 0 C shows that these samples are more sensitive towards CO2 gas, so this sensor is selective to CO2 gas more than NO. These results confirm that MoO3−x film deposited on glass of 500 nm thick can solve a large section of detecting CO2 gas problems such as selectivity, sensitivity to low gas concentrations, short response, recovery time, reversibility and low working temperature. Finally, the MoO3−x films (with thickness of 500 nm) deposited on FTO substrate was examined as gaseous HCl sensor at room temperature. It manifests a very high sensitivity towards gaseous HCl but cannot be applied for detecting it due to irreversibility and no stability of their properties after HCl vapor adsorption.

Molybdenum Oxide Coatings Deposited on Plasma Nitrided Surfaces

Molybdenum trioxide (MoO3) thin films are generally deposit on metallic surfaces to increase their tribological performance. In this manuscript, MoOx coatings were for the first time deposited on plasma nitrided surfaces. Vickers microhardness tests, X-ray diffractometry, and micro abrasive wear tests characterized the samples. It was investigated the effect of temperature in hardness and tribological properties of austenitic stainless steel surfaces. When the temperature of plasma nitriding increases, the coating thickness and the nitrogen diffusion on the treated surface also increases, favoring the hardness of the coatings. After MoOx deposition, the predominant MoO3 phase with monoclinic and orthorhombic unit cells was observed. MoOx coatings after plasma nitriding demonstrated the highest wear resistance.

Study of thermochromic and photocatalytic properties of MoO3 thin films

Molybdenum trioxide (MoO 3 ) thin films with thicknesses 300, 400 and 500 nm were deposited on an FTO substrate by thermal evaporation method. The prepared thin films showed both thermochromic and photocatalytic dye degradation properties. The thermochromic property of the prepared thin films was induced by exposing the thin films to argon gas at a temperature varying from 100 °C to 300 °C (in steps of 50 °C). The photocatalytic dye degradation ability of the films were examined by the photodegradation of methylene blue (MB) dye solution under visible light irradiation. MoO 3 thin film with 300 nm thickness is seen to have good thermochromic and photocatalytic dye degradation ability and both of these properties are necessary for smart window applications. • Synthesis of MoO 3 thin films by thermal evaporation method. • Thermochromic property of MoO 3 thin films. • Photocatalytic activity under direct sunlight irradiation. • Promising thin film for eco-friendly smart window application.

Electrochromism in MoO3 nanostructured thin films

Molybdenum trioxide thin films were grown onto well cleaned Indium Tin Oxide coated glass substrate by Pulsed Laser Deposition technique in presence of oxygen partial pressure about 100 mTorr and at several substrate temperature (T s ) ranging from 100 °C to 400 °C. Systematic characterisation of grown films is employed in order to study the growth of films, structure, optical and electrochromic properties. Presence of only Mo and O elements in Energy Dispersive Spectra of grown films stated that the films were pure without any contaminants. The films were showing mixed α and β phase at T s = 100 °C and slowly turns to α-phase with rise of substrate temperature to 400 °C. The grain size was observed to be increased in the films deposited up to 300 °C which is supported by Scanning Electron Microscopic and Atomic Force Microscopic images. The variation in the optical transmittance , bandgap and electrochromic efficiency with respect to substrate temperature are clearly discussed in this research paper. • MoO 3 films were deposited by PLD technique under PO 2 ≈100 mTorr at various substrate temperatures ranging from 100 °C–400 °C. • The films deposited were found to be homogeneous, uniform and pure. • The films showed mixed phase of α-β up to T s = 200 °C and turns to α- phase from 300 °C. • The optical bandgap values increased with substrate temperature up to 300 °C and then decreased for films deposited at 400 °C. • The films exhibit maximum electrochromic efficiency for the films deposited at T S = 300 °C.

Magnetic, Optical and I-V Characteristics of MoO3 thin films

Molybdenum trioxide (MoO3) thin films with cobalt concentration were grown on quartz and n-type Si (100) by thermal evaporation deposition technique. Then the films were thermally annealed for 2 hours under normal environment. The structure is analyzed by X-Ray Diffraction (XRD) to confirm the orthorhombic α-MoO3 phase confirming the crystallinity of thin films. Furthermore, the morphological study is done by Scanning Electron Microscope (SEM) to confirm granular shaped interconnected films. Thicknesses of films are determined by Ellipsometry which vary from 40nm to 140nm with the decrease in Cobalt concentration of thin films. Modifications in optical properties due to the doping of Cobalt in MoO3 thin films are studied in terms of transmittance data and Taucs plot. All films represent direct band gap transitions. The band-gap of MoO3 comes out be 3.32eV from the Taucs plot. A slight change in the band-gaps is found for various films with different concentration. Vibrating Sample Magnetometer (VSM) results studied at the room temperature confirm the introduced magnetic property as well as the hysteresis loop for the Cobalt doped MoO3 thin films.

Photochromic Performance of PLD grown MoO3Thin Films

Molybdenum trioxide (MoO3) thin films are made by Pulsed Laser Deposition (PLD) technique onto cleaned glass substrates at an oxygen partial pressure (PO2) of 100 m Torr by varying substrate temperature (Ts). The present study describes the variation in the growth of films and photochromic properties with respect to substrate temperature. XRD studies confirm unique α - orthorhombic layered structure for grown films and the intensity of prominent peaks increases with substrate temperature. SEM images discloses that the film surface constitutes uniformly spherical grains at lower substrate temperature (Ts = 100 ℃) and turns to needle like structure as substrate temperature reaches to 200 and 300 ℃. The films deposited at 400 ℃ gives nano-crystalline structure which shows stable and high photochromic efficiency. The studies also reveal that the presence of impurities or ions on the surface of the film and effects on the photochromic performance.

The preparation and investigation of all thin film electrochromic devices based on reactively sputtered MoO3 thin films

Reactively sputtered molybdenum trioxide (MoO3) thin films were systematically investigated and employed as cathodic electrochromic layers in all thin film electrochromic devices (ATF-ECDs). The gas loop controller was employed for adjustment of inputted oxygen gas flux by monitoring the target voltage during reactive sputtering. The working pressure played a great role on the deposition rate, crystallite size, optical properties and the electrochromic properties of MoO3 and the applied ATF-ECDs (soda lime glass (SLG)/ITO/NiOX/Ta2O5/MoO3/ITO). A 4 Pa MoO3 based ATF-ECD achieved a high optical modulation (transmission @ 600 nm) of ~50% and a high coloration efficiency of 149.4 cm2/C.

A Facile Synthesis for Studying the Effect of Molar Concentration on Structural, Morphological and Optical Behaviour of MoO3 Thin Films using Jet Nebulizer Spray Pyrolysis Technique for n-MoO3/p-Si Photodiode Application

In this study, molybdenum trioxide (MoO3) thin films were coated with various Mo concentrations 1, 2, 3 and 4 wt.% referred as L1, L2, L3 and L4 respectively on to the silica substrate calcined at 450 ºC by a facile, rapid cost-effective and a custom-made jet nebulizer spray pyrolysis (JNSP) technique. The concentration impact on the structural, morphological and compositional parameters were examined by XRD, FESEM, EDX, FTIR and Raman studies. The XRD peaks confirmed the presence of the orthorhombic phase of MoO3 (α-MoO3) in the prepared films. FESEM images depicted their nanorod structured morphology. EDX spectra confirm the presence of elements such as oxygen (O) and molybdenum (Mo). Molecular fingerprint of the samples were diagnosed by probing their molecular vibrations through the Raman Spectroscopy. Vibrational frequencies of the bonds in the samples was investigated by FTIR. The I-V measurements were analyzed in light and dark conditions for the n-MoO3/p-Si junction diode.

Study of molybdenum trioxide thin film deposited using dip coating method

Abstract Molybdenum trioxide with its varied properties has been used in various field like electrochromics devices, gas sensors, rechargeable lithium ion battery, solar cells etc. which makes it an attractive materials. Particularly, α-MoO3 phase with (0k0) orientation corresponding to the orthorhombic phase is widely used for sensing applications due to its layered structure. With economical and chemical route, MoO3 thin film deposition using dip coating method is presented. The ammonium heptamolybdate was used as source of molybdenum, DI water as solvent for the dip coating and monoethanolamine as a binding agent. The effect of annealing on the dip coated thin films at temperatures 250 °C, 350 °C and 450 °C was studied. The structural and optical properties of the prepared thin films were studied using X-Ray diffraction technique and UV–Visible spectroscopy respectively. XRD reveals that the crystalline nature of the film increases with increase in annealed temperature. The thin film annealed at 450 °C temperature exhibits highly (0k0) oriented orthorhombic structure with crystallize size of 16 nm. Moreover, the Surface morphology and Stoichiometry of the 450 °C annealed film was studied with the help of Scanning electron microscopy and Energy dispersive X-ray analysis.

Effect of Substrate Temperature on the Growth of Molybdenum Trioxide Thin Films

Molybdenum oxide is one of the most important inorganic material, which exhibits several phases, such as MoO3, MoO2, Mo4O11, Mo5O14, etc. Among them, molybdenum trioxide (MoO3) can crystallize in various phases, such as orthorhombic, monoclinic etc., which makes it useful for possible applications in chemical, electrical and electrochemical industries. In this work, MoO3 films were obtained by pulsed laser deposition by varying the substrate temperature from room temperature to 400°C. The thin films were deposited on fine cleaned glass substrates coated with fluorine tin oxide under a pressure of 10–5 mbar. X-ray diffraction patterns display two polymorphic phases of MoO3 (α and β), but no other phases are observed, and the structure changes from orthorhombic to monoclinic. The substrate temperature strongly influences the structure and surface topography. Morphological studies show the surface homogeneity, crack-free, layered structure and crystallinity of the films. The band gap of the obtained MoO3 thin films increases from 3.0 to 3.39 eV with increasing substrate temperature from room temperature to 400°C.