Characterization Of ZnO Thin Films Research Articles

Boron-Doped Thin Films Fabricated by the Spin Coating Method: The Effect of Doping Concentrations

This work examined the impact of different levels of B-doping on the structural, morphological, optical, and electrical characteristics of ZnO thin films. Boron-doped zinc oxide thin films were deposited on glass substrates using the spin-coating technique. The B concentrations employed were 1, 2, 3, 4, and 5 at. %. The systematic characterizations manifest that the properties of the deposited films were heavily influenced by changing concentrations of B doping. It was found that as the concentration of B-doping increases, the values of grain size decrease. In addition, it was observed that ZnO thin films containing a lower concentration of B dopant exhibited higher transparency. Finally, it was figured out that the resistivity of the films declines dramatically with a higher content of B-doping. The results of our research may initiate further inquiries into the creation of superior thin films.

Impact of Mo doping on photo-sensing properties of ZnO thin films for advanced photodetection applications

This work explored the impact of Mo-doping on the structural, optical, photophysical, and electrical characteristics of ZnO thin films and their potential application to the UV light detection properties was investigated. The hexagonal structure of the films without any impurities or extra phases was confirmed by X-ray diffraction and FT-Raman spectroscopy. The crystallite size reduced from 36 nm to 25 nm with the addition of 3 wt% of Mo in ZnO. The EDX/SEM e-mapping verified the elemental composition and uniform Mo doping throughout the films. The FESEM images revealed spherical nanoparticles with smaller grains size for higher Mo-doping levels. The absorption spectra were recorded from UV to NIR range, and the bandgap was observed to increase from 3.25 eV for pure ZnO to 3.42 for 3% Mo-doped ZnO sample. The Mo-doped ZnO film showed PL quenching, which indicates charge transfer and suppression of defect sates in the ZnO films via Mo-doping. The time-resolved fluorescence spectra (TRFS) of these films revealed that the carrier lifetime increased from 80 ps for pure ZnO to 144 ps for 3% Mo-doped ZnO thin film. The electrical parameters including resistivity, carrier mobility, concentrations, and sheet resistance of fabricated films were evaluated by Hall-effect measurement. The resistivity and mobility were observed to decrease from 9.33×104 Ω.cm, 55.1 cm2/V.s to 2.03×103 Ω.cm 15.4 cm2/V.s for 3% Mo-doped ZnO thin film, while carrier density increased. The photodetection study demonstrated that the responsivity, detectivity, external quantum efficiency and response time of devices were significantly enhanced with Mo idoping.

Effect of aging on transmittance, and effect of annealing temperature on CO2 sensing of ZnO thin film deposited by spin coating

Investigations have been made on the structural, morphological, optical, sensing, and aging characteristics of ZnO thin films created on glass substrate using the sol-gel spin coating process. Zinc acetate (ZnAc), ethanol, and stearic acid were employed as the starting materials, solvent, and stabilizer, respectively, to deposit the ZnO thin films on the blue star glass substrate. An UV–visible spectrophotometer is used to study the optical characteristics. With the aid of XRD and FESEM characterization techniques, the structural and morphological properties are studied. The results showed that the characteristics of ZnO thin films were strongly dependent on the annealing temperature. The XRD measurement indicated that the deposited film shows the hexagonal structure and preferential orientation along the (002) crystal plane with a grain size of 78.99 nm. The transmittance value of the ZnO films was relatively high up to 90 %. The result showed that the transmittance value is strongly dependent on the aging time of the sample. The SEM images show that morphology and texture are dependent on the annealing temperature. The SEM image also contains a foreign object or xenolith. The V-I characteristics show nonlinear behavior, and the resistance of the thin film is between 2800 and 5000 MΩ. The CO2 sensing at 450 °C is far better than that of at 750 °C. The response time at 450 °C is 20–40 s, the recovery time is better at 750 °C.

Sol-gel synthesis, characterization of ZnO thin films on different substrates, and bandgap calculation by the Tauc plot method

The sol-gel spin coating method was used for the preparation of the Zinc Oxide which was coated over polymer, transparent, and glass translucent substrates and characterized with the help of a UV-Vis Spectroscope. The wavelength bandgap of those samples was found to be 296nm, 310.5nm, and 330nm respectively. The actual band gap of ZnO is 388nm. Similarly, their optical bandgap energy calculated by the Tauc Plot method were 3.641eV, 3.385eV, and 3.495 eV respectively. The transparent polymer slide has the lowest wavelength bandgap and the translucent glass slide has the highest. Further, the bandgap’s value differs from its actual value to the difference in the absorption process due to the presence of the substrate. These results suggest that the choice of substrate can significantly impact the optical properties and performance of the zinc oxide thin film. This result can be applied in developing and optimizing zinc oxide thin films for various purposes, such as in solar cells, sensors, and optoelectronics. By carefully selecting the substrate, it may be possible to tailor the bandgap energy and other optical properties of the thin film to better suit the specific application.

Exploring the effects of substrate and substrate temperature on the properties of radio frequency magnetron sputtered ZnO thin films

The physical and optical properties of zinc oxide thin films strongly depend on the film deposition techniques. In this work, RF magnetron sputtering was used to deposit ZnO thin films on various substrates (glass, quartz, ITO-coated glass, FTO-coated glass, Si(100), Si(100)/ SiO2) to study the role of substrate and substrate temperature on the morphological, structural and optical properties of the film grown. A detailed discussion on various aspects like surface morphology, strain, photoluminescence, bandgap, surface roughness, and material composition has been done. Compressive stress was present in the films created at room temperature and differed for various substrates based on the lattice mismatch. The nature and temperature of the substrate are found to affect the surface topography of films. Substrate and substrate temperature influenced the emission characteristics of ZnO thin films. In oxygen-rich substrates, defect emissions differed. We found that quartz is a better substrate to fabricate ZnO at room temperature and both Si and Si/SiO2 are preferable at high temperatures due to the lower lattice mismatch and thermal expansion coefficient. Comparing the electrical characteristics of ZnO thin films grown on glass and quartz substrates, ZnO on glass exhibited lower resistivity and higher carrier concentration. The Triboelectric nanogenerator (TENG) combining ZnO and PDMS, was developed to operate in vertical contact-separation mode. The obtained open circuit voltage was 30 V and 33 V for ZnO grown over ITO and FTO respectively, and the slight increase is due to the rougher film's surface on FTO than ITO. The selection of substrate is crucial in many applications and our findings provide an overview of the suitability of substrate and substrate temperature for the fabrication of ZnO thin film-based optoelectronic devices.

Effects of power and temperature on the structural, anti-icing, wettability, and optical properties of zinc oxide thin films

Zinc oxide semiconductors have received significant research attention over the past decade owing to their diverse applications. In this paper, we report the development and characterisation of ZnO thin films prepared by radio-frequency (RF) magnetron sputtering. The optical, anti-icing, wettability, and structural properties of the films were investigated at various sputtering power levels and temperatures. With an increase in the power from 175 to 250 W, the ZnO thin films showed fine (002) structures. X-ray diffraction analysis of the coated thin films revealed a considerable increase in the (002) peak intensity along the c-axis with increasing power and temperature. Increasing the sputtering power from 175 to 250 W and the deposition temperature from 150 to 300 °C led to an increase in the average size of the grains from 10.548 to 13.151 nm and from 9.97 to 13.151 nm, respectively. The water contact angle possibly depends on the RF power and temperature employed for material deposition. Within the 350–800 nm range, the prepared films achieved optical transmissions of 92%–88%, refractive indices of 1.52–1.50, and band gaps of 3.28–3.24 eV. The anti-icing properties were also improved by adjusting the sputtering power and temperature during material deposition.

Synthesis And Structural Feasibility Of Photonic Materials

Aim: Studying the optical-thermal dependence of liquid crystal based on the quantity data of image texture is essential to get more information accurately Background: In this research, the optical-thermal dependence of chiral nematic liquid crystals ink sample was investigated based on the sample's texture and colour changes at various temperatures. Objective: The structural and optical characteristics of ZnO thin films are investigated in this study. While spinning at 4000 rpm for 30 seconds at room temperature, the zinc oxide solution was spun onto a pre-cleaned, glass substrate, creating the desired layer thickness. method: This was followed by annealing at 150°C-600°C in 50°C steps, which was carried out on the samples. An ultraviolet-visible spectrophotometer and a scanning electron microscope were used to analyse the optical properties of this thin coating. Method: This was followed by annealing at 150°C-600°C in 50°C steps, which was carried out on the samples. An ultraviolet-visible spectrophotometer and a scanning electron microscope were used to analyse the optical properties of this thin coating. Result: Zinc oxide's optical band gap was determined by measuring its optical transmittance, reflectance, and absorbance. Photonic crystals can exhibit relevant optical properties when transmitting or reflecting a light beam. conclusion: In particular, in a two-dimensional photonic crystal, the reflective properties can be of interest and consequently optimized for different technological applications such as tuneable laser cavities, photovoltaic solar systems, and selective high reflection mirrors, among many others. Conclusion: In particular, in a two-dimensional photonic crystal, the reflective properties can be of interest and consequently optimized for different technological applications such as tuneable laser cavities, photovoltaic solar systems, and selective high-reflection mirrors, among many others.

PHOTOCATALYTIC DEGRADATION OF RHODAMINE B UNDER UV USING DOUBLE-LAYER ZnO: Fe THIN FILM

Waste dyes are a major source of water pollution, which is a critical environmental issue. The purpose of this study is to synthesize double-layer ZnO: Fe 5-20% thin films and investigate the degradation of rhodamine B in these films. The creation of the ZnO phase with the wurtzite hexagonal structure may be seen in the thin film X-ray diffraction pattern. Only marginally lessened energy bandgap (3.11-3.09 eV), optical transmission spectra, and lattice strain was seen after Fe was added to ZnO thin films. With increasing Fe concentration, it was found that the hydrophilicity and photocatalytic characteristics of ZnO thin films considerably decreased, as shown by the contact angle going from 51.4 to 70.71 and the decomposition efficiency going from 61.46% to 50.35%. The double-layer ZnO layer's optical characteristics diminish as the Fe concentration rises.

Correlation Between the Structural, Morphological and Optical Characteristics of ZnO Thin Films Prepared by Thermal Evaporation

Correlation Between the Structural, Morphological and Optical Characteristics of ZnO Thin Films Prepared by Thermal Evaporation

Synthesis and characterization of Zinc Oxide thin films deposited by Spray Pyrolysis technique for possible applications in solar cells

In the present study, the synthesis and characterization of ZnO thin films deposited at 300, 350 and 400°C using the Ultrasonic Spray Pyrolysis technique, as a possible candidate for electron transport layer (ETL) in solar cells is reported. X-ray diffraction (XRD) analysis revealed that the films have a hexagonal wurtzite phase with a preferential orientation (101) with good polycrystallinity. The mean crystallites size based on the Debye-Scherrer model was calculated, indicating that the size of the crystals decreases as the deposition temperature increases. The optical characterization of the material showed a high transmittance in the visible region (85-99%) with which the optical band gap (3.06-3.29 eV) was determined. The thickness, surface roughness and optical constants (n and k) were determined by Spectroscopic Ellipsometry using the Gaussian oscillator model. Hall Effect revealed a low resistivity of 1-4 Ω cm and a high mobility of charge carriers (304 cm2/Vs) in the films. Due to all these properties, ZnO is considered an ideal material for optoelectronic applications, as well as a material with potential to be used as ETL in solar cells.

Effect of Na doping and heat treatment on the characteristics of ZnO thin films and ZnO/Si cells

• Undoped and Na doped ZnO films and ZnO/Si cells fabricated by chemical spray pyrolysis. • Band gap energy and resistivity of ZnO thin films decreased with Na doping and thermal annealing. • Power conversion efficiency of ZnO/Si heterojunction cell remarkably increased with Na doping and thermal annealing. Undoped and sodium doped ZnO thin films were grown on glass and Si substrates by spray pyrolysis. Post thermal annealing was applied for 1 h at 350 °C. Effect of Na doping and thermal annealing on the properties of ZnO thin films were investigated via XRD, UV–Visible spectrometry and resistivity measurements. Resistivity of the Na doped and annealed ZnO film was decreased to 7.15x10 3 Ω.cm from 3.26x10 4 Ω.cm where band gap energy was decreased to 3.31 eV from 3.36 eV. Current-voltage measurements held for all ZnO/Si heterostructures in dark and under illumination and device parameters were determined. Again best result obtained for the device in which both Na doping and annealing were applied as efficiency was increased to 4.57% from 2.01%.

Design And Fabrication Of A Low-Cost Dip Coating System For Depositing Homogeneous And Transparent Zno Thin Films

ZnO has a resistivity of up to 104 Ω cm-1 in most cases. Nevertheless, by increasing the layer thickness, the resistivity decreases as well, resulting in greater current transport. The dip coating system was developed to prepare the ultra-thin film, it relied on a controller, stepper motor and some low-cost recycled materials. Thin films of ZnO were successfully deposited on indium tin oxide substrates. The effects of the dipping cycles were investigated. Dipping processes were applied several times (1, 2, and 3) for the same concentrations (0.1) M to obtain homogeneous thin films. X-ray diffraction showed that the structure of ZnO is hexagonal Wurtzite. The crystals were in the nanoscale size range as (19.18, 24.76, and 31.29) nm. As for the examination by FESEM, it was found that homogeneous layers formed when increasing the number of times of coating for the prepared thin films. High transmittance, decreasing in energy gap, and suitable surface resistance ZnO thin films were achieved. In the wavelength range of 190 – 1100 nm, the thin films had an optical transmittance of up to 87%. The sheet resistance values were determined to be 19.202 Ω sq-1 indicating that the characteristics of ZnO thin films have improved. The dip coating device is designed to be easy to use, inexpensive and economic in terms of using the raw materials. This low-cost manufactured device contributes to scientific development for researchers who are unable to buy expensive devices that perform the same purpose and give the same results.

ИЗУЧЕНИЕ ОПТИЧЕСКИХ СВОЙСТВ ТОНКИХ СЛОЕВ ОКСИДА ЦИНКА ZnO, ПОЛУЧЕННЫХ ЗОЛЬ-ГЕЛЬ МЕТОДОМ

Currently, the actual direction is the search for functional layers for various optoelectronicdevices. A promising candidate as a basis for many such structures is zinc oxide (ZnO), whichcombines a number of unique optical and photoelectric properties. However, the characteristics ofZnO thin films can vary significantly depending on the chosen synthesis method and specific productionconditions. One of the varieties of the sol-gel method suitable for the synthesis ofnanoscale films is the dip-coating method. The paper presents the results of the synthesis of thinfilms of zinc oxide on glass substrates by the method of vertical drawing from ZnO alcohol sol.The effect of the elongation rate on the structural and optical properties of synthesized ZnO filmswas studied using spectral ellipsometry and spectral photometry. By the method of spectralellipsometry, it was found that the change in the rate of elongation significantly affects the thicknessand porosity of the synthesized zinc oxide layers. The analysis of the obtained dependence ofthe film thickness on the pulling speed showed that in the vertical pulling method, the growth ofzinc oxide on glass substrates can be realized in two modes: in capillary forces mode and in dryingmode. At the same time, transmission spectra were measured for synthesized ZnO films byspectral photometry, the analysis of which showed the effect of the elongation rate on the positionof the edge of fundamental absorption. It was found that the main cause of the resulting.

Preparation and Characterization of ZnO Thin Film on Anodic Al2O3 as a Substrate for Several Applications

Preparation and Characterization of ZnO Thin Film on Anodic Al2O3 as a Substrate for Several Applications

Nitrogen incorporated zinc oxide thin film for efficient ethanol detection

Zinc oxide which is a n-type semiconducting metal oxide (SMO) has been a promising material for detecting ethanol vapor. However, pure ZnO based ethanol sensors often suffer from high working temperature, cross sensitivity towards methanol and poor stability against humidity. Here in we report improving the ethanol sensing characteristics of ZnO thin films by substitutional nitrogen doping. Ethanol sensing characteristics of the N-ZnO thin film has been compared with pure ZnO sensor over a wide range of temperature and relative humidity conditions. The N-ZnO sensor exhibits significantly large ethanol sensing response at a lower operating temperature (~99% at 225 °C vs ~81% at 250 °C for ZnO), faster response time (12 s vs 33 s for ZnO), long term stability, improved resilience against humidity and selectivity towards ethanol over other VOCs. The experimental observations have been supplemented by estimating the adsorption energies of ethanol on ZnO and N-ZnO surface using density functional theory (DFT) calculations. We discuss that the microscopic origin of improved ethanol sensing of N-ZnO is related to the facile adsorption of ethanol molecules on the oxide surface which is promoted by modification of electronic properties of ZnO by the nitrogen dopant atoms.

The effect of solution pH on the structural, surface morphological, and optical characteristics of ZnO thin films synthesized by the chemical bath deposition technique

The presented work utilizes the chemical bath deposition technique to fabricate zinc oxide nano-thin films on a glass substrate. The quality of synthesized films is dependent on the deposition parameters, which include the solvents and metal salts used, as well as the bathing time and temperature. The impact of the pH value of the solution on the crystal structure, surface morphological, and optical characteristics of zinc oxide thin films was studied in this respect. An XRD diffractometer was used to determine the structural characteristics; a scanning electron microscope was utilized to analyze the surface topology. The linear optical properties were carried out using a UV–VIS spectrometer. The XRD results showed an increase in grain size from 36.06 nm to 42.23 nm as the pH value increased from 8 to 10. The Debye-Scherrer method was utilized to assess crystal grain size and microstrain along (1 0 1) orientation. SEM images showed a significant correlation between grain size distribution and precursor’s solution pH. All the deposited films have shown more than 86% optical transparency, suggesting that these obtained films are best suitable for transparent conducting electrodes for display devices. However, the optical transparency of the deposited films has decreased with an increase in pH value, which may be attributed to increased film thickness. The sample deposited at pH: 10 exhibited the minimal optical bandgap of all the samples.

UV detector characteristics of ZnO thin film deposited on Corning glass substrates using low-cost fabrication method

UV detector characteristics of ZnO thin film deposited on Corning glass substrates using low-cost fabrication method

Impact of Sn doping on the hydrogen detection characteristics of ZnO thin films: Insights from experimental and DFT combination

The development of efficient chemical sensors based on semiconductor oxides is a major challenge. Low-cost equipment fabrication with a high sensor response towards H2 was the aim of our work. Chemical sensors were elaborated using zinc oxide, aluminum- and tin-doped zinc oxide. The samples were synthesized with a cost-effective chemical spray pyrolysis technique. Sn-doped ZnO response to hydrogen gas is the highest followed by ZnO and Al-doped ZnO, with a high sensitivity reaching 200 at 500 ppm, for 400 °C. DFT calculations revealed that O2 is strongly adsorbed on the ZnO-Al surface, resulting in the cancellation of the electrical conductance. Consequently, the approaching H2 gas will not possess sufficient energy to extract the strongly adsorbed oxygen from the surface, and no trapped electrons can be released back to the surface. In contrast, DFT calculations highlighted the potential of ZnO and Sn-doped ZnO to be used as hydrogen gas sensors. Charge transfer analysis revealed that only a small release of the trapped electrons occurs on the pure ZnO surface (0.14|e|), compared to Sn doped ZnO, in which a full release of free electrons was observed, resulting in a more favorable response to H2 and confirming the experimental results.

Growth and characterization of ZnO thin films at low temperatures: from room temperature to − 120 °C

ZnO thin films have been grown by e-beam evaporation in the range from room temperature to − 120 °C on two types of substrates, Al2O3 (0001) and Si (100). Although the ZnO/Al2O3 system has been thoroughly characterized, including optical and electrical techniques, the morphological, structural and chemical properties show no significant differences between both substrates. Thus, the general features of the ZnO growth mode at low temperature can be generalized. The relatively low growth temperatures reduce the diffusion of atoms at the surface, which leads to morphological and chemical changes. As the temperature decreases, the growth mode changes from a van der Drift model to a gradual bilayer system composed of an interfacial layer in contact with the substrate and a second columnar-based layer. This second well-ordered film disappears for the lowest temperatures while a Zn-rich interface in contact with the substrate emerges. Precisely from this interface, Zn-rich whiskers develop under the ZnO film and cause the loss of adhesion at temperatures below − 100 °C. These extreme temperatures also affect the crystal size, lattice strain, and total amount of oxygen vacancies. The behavior of the optical and electrical properties in terms of band gap, transparency, electrical resistivity, and Seebeck coefficient is discussed in the light of structural and chemical characterization. Samples grown at 0 °C exhibit an enhanced transmittance compared to those grown at room temperature while preserving similar electrical resistivity values and natural n-type doping. These results open a promising route to enhance ZnO films properties below the typical high temperature window.

Enhancing the Conductivity of the Nanostructured ZnO Thin Film by Vacuum Annealing

ZnO thin films were successfully synthesized using a facile chemical route and were characterized employing X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and photoluminescence (PL) analysis. The obtained precursor was spin-coated on Si(100)/SiO2 wafers, then the substrates were divided into two groups for the thermal annealing at ambient and vacuum conditions. Morphological characterization showed the formation of nanoflowers and porous structures at different annealing conditions. The effect of vacuum annealing on the current-voltage characterization of ZnO thin film has been presented to inspect the role of annealing condition in device fabrication. The electrical properties of the ZnO thin films were performed in the temperature range of 75–[Formula: see text]C. At [Formula: see text]C, the ambient annealed sample presents the current value of 10[Formula: see text][Formula: see text]A for 5[Formula: see text]V, and the vacuum annealed sample reaches the maximum current of 3.1[Formula: see text]mA for the same operating voltage. The presence of oxygen vacancies notably affects the electrical properties of ZnO thin films.