Properties Of Thin Films Research Articles

Realization of ferroelectricity in sputtered Al1-xScxN films with a wide range of Sc content

The ferroelectric properties of wurtzite-structured Al1-xScxN thin films are affected simultaneously by the Sc concentration and in-plane stress state, however, the interaction between these two factors remains unclear. In this work, a series of Al1-xScxN films were deposited on (111) Si substrate by dual-target co-sputtering. X-ray diffraction analyses show the films with a wide range of Sc content (x= 0.05 - 0.50) have the (0002)-textured wurtzite structure and are in compressive stress state. Ferroelectricity in all the films is confirmed by polarization hysteresis loop measurements at room temperature, and the coercive field exhibits an interesting non-monotonic transition due to the competition between in-plane stress and Sc incorporation. The results provide insight into the wurtzite-structure stability and the nature of ferroelectricity for Al1-xScxN thin films.

Structure, magnetic and magnetocaloric properties of the Mn5Ge3 thin film grown on Si(111)

Structure, magnetic and magnetocaloric properties of the Mn5Ge3 thin film grown on Si(111)

Modification of WS2 thin film properties using high dose gamma irradiation

The tunability of the transition metal dichalcogenide properties has gained attention from numerous researchers due to their wide application in various fields including quantum technology. In the present work, WS2 has been deposited on fluorine doped tin oxide substrate and its properties have been studied systematically. These samples were irradiated using gamma radiation for various doses, and the effect on structural, morphological, optical and electrical properties has been reported. The crystallinity of the material is observed to be decreased, and the results are well supported by x-ray diffraction, Raman spectroscopy techniques. The increase in grain boundaries has been supported by the agglomeration observed in the scanning electron microscopy micrographs. The XPS results of WS2 after gamma irradiation show evolution of oxygen, carbon, C=O, W–O and SO4 −2 peaks, confirming the addition of impurities and formation of point defect. The gamma irradiation creates point defects, and their density increases considerably with increasing gamma dosage. These defects crucially altered the structural, optical and electrical properties of the material. The reduction in the optical band gap with increased gamma irradiation is evident from the absorption spectra and respective Tauc plots. The I–V graphs show a 1000-fold increase in the saturation current after 100 kGy gamma irradiation dose. This work has explored the gamma irradiation effect on the WS2 and suggests substantial modification in the material and enhancement in electrical properties.

Enhanced photoluminescence characteristics in Mg doped Alq3: An insight into doping mechanism

The present paper deals with the investigations on the effect of Mg doping on the structural and photophysical properties of Alq3 thin films. Mg doped Alq3 powders, with varying Mg concentrations, are synthesized using co-precipitation method and their thin films are deposited using vacuum evaporation method. These films are subjected to different analytical analyses to study the effect of Mg doping on the structural and photophysical properties of Alq3. It has been observed that Mg is attached at the central part of the Alq3 molecules making bonds with Al, N and O atoms. In this process, Mg atoms transfer electrons to Alq3 molecules and increases the electron density in its highest occupied molecular orbital (HOMO). Increased HOMO electron density in Mg doped Alq3 results in the improvement in its photoluminescence characteristics. Highest photoluminescent characteristics are observed for Mg doped Alq3 having 1.5 % (by mole) Mg which shows almost 2-fold enhancement in photoluminescence quantum efficiency (PLQY) and 3-fold enhancement in radiative decay rate. The results obtained in this work suggest that Mg doped Alq3 films may be integrated in high performing organic light emitting devices.

Influence of Flow Rates and Flow Times of Plasma-Enhanced Atomic Layer Deposition Purge Gas on TiN Thin Film Properties

Influence of Flow Rates and Flow Times of Plasma-Enhanced Atomic Layer Deposition Purge Gas on TiN Thin Film Properties

Studies on the structural, optical, and optoelectrical properties of innovative Li2ZnSnS4 thin films deposited by nebulizer spray pyrolysis

Studies on the structural, optical, and optoelectrical properties of innovative Li2ZnSnS4 thin films deposited by nebulizer spray pyrolysis

Integration Of Solution‐Processed BaTiO3 Thin Films with High Pockels Coefficient on Photonic Platforms

AbstractThe heterogeneous integration of ferroelectric BaTiO3 thin films on silicon (Si) and silicon nitride (SiN)‐based platforms for photonic integrated circuits (PICs) plays a crucial role in the development of future nanophotonic thin film modulators. Since the electro‐optic (EO) properties of ferroelectric thin films strongly depend on their crystal phase and texture, the integration of BaTiO3 thin films on these platforms is far from trivial. So far, a conventional integration route using a SrTiO3 template film in combination with high vacuum deposition methods has been developed, but it has a low throughput, is expensive and requires monocrystalline substrates. To close this gap, a cost‐efficient, high‐throughput and scalable method for integrating highly textured BaTiO3 films is needed. Therefore, an alternative method for the integration of highly textured BaTiO3 films using a La2O2CO3 template film in combination with a chemical solution deposition (CSD) process is presented. In this work, the structural and EO properties of the solution‐processed BaTiO3 film are characterized and its integration into an optical ring resonator is evaluated. The BaTiO3 film exhibits a fiber texture, has a large Pockels coefficient (reff) of 139 pm V−1, and integration into a ring resonator‐based modulator shows a VπL of 1.881 V cm and a bandwidth of > 40 GHz. This enables low‐cost, high‐throughput, and flexible integration of BaTiO3 films on PIC platforms and the potential large‐scale fabrication of nanophotonic BaTiO3 thin‐film modulators.

Modification of PEDOT:PSS thin film properties using pyridine-based solid additive for optoelectronic applications

Abstract Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) is one of the most promising hole transport layers that is widely used in high-performance optoelectronic devices. However, the hygroscopic nature and acidity of PEDOT:PSS is known to cause degradation in devices and decrease their performance. In this study, a new pyridine solid additive, 2,3-dihydropyridine (2,3-DHP) was incorporated into the PEDOT:PSS solution to improve its characteristics. A low-temperature solution-based spin-coating device was utilized to produce the thin films. From the results, the PEDOT:PSS@2,3-DHP (1 wt%) exhibited excellent optical characteristics. It also provided informative and controlled morphology when it was annealed at 100 oC, suggesting that PEDOT:PSS@2,3-DHP has a potential advantage in photovoltaic (PV) devices. Moreover, in the photodetection experiment utilizing LED of 380 nm, PEDOT:PSS@2,3-DHP showed a higher photocurrent response when compared with pristine PEDOT:PSS. It also significantly reduced sheet resistance and achieved superior electrical conductivity. Interaction between the 2,3-DHP, PEDOT, and PSS chains altered the mechanical properties of the PEDOT:PSS, leading to the modification in structural and electrical characteristics. Overall, these findings highlight the importance and applicability of PEDOT:PSS@2,3-DHP in a wide range of optoelectronic devices.

Effect of particle size on optical and electrical properties of thin films – a simulation approach

This paper presents a simulated investigation of the relationship between surface roughness and particle size as well as the resulting impact of the both on the thin film’s physical and optical properties. Non-porous thin films are created through computer simulation for a range of particle sizes following the random deposition with a surface relaxation approach. For the deposited thin films different fundamental parameters like transmittance, reflectance, absorption coefficients, frequency dependent dielectric constants, loss angle, refractive indices, optical band gap have all been calculated and in this process of calculation the fundamental values of two different materials; zinc oxide (ZnO and cadmium selenide (CdSe) are taken. It has been seen that when the particle sizes are comparable the calculated values of optical band gap of both ZnO and CdSe matches well with the experimental values of the same reported by others. This is probably the first effort to develop a direct relation between the particle size with different fundamental optical properties of different materials through simple simulation which agrees well with the experimental result. This would definitely help the experimental researchers in the field of material science to design their experiments as per the desired requirements.

Advancement of electro-optical properties through changes in the physicochemical composition of hybrid thin films by doping reduced graphene oxide into a sol-gel process solution.

A hybrid thin film was fabricated by doping graphene oxide into a sol-gel solution containing a mixture of zirconium, bismuth, and indium oxide. The thin film was fabricated using a brush coating process. The graphene oxide doping ratios used were 0, 5, and 15 wt%. During the thin film fabrication process, the produced sol-gel solution generates a contractile force due to the shear stress of the brush bristles, resulting in a microgroove structure. This structure was confirmed through scanning electron microscopy analysis, which revealed the clear presence of rGO. Comparing the electrical properties of a zirconium bismuth indium oxide thin film without graphene oxide doping and a thin film doped with 15 wt% graphene oxide, the electro-optical properties were significantly improved with graphene oxide doping. In general, the threshold voltage decreased by approximately 0.42 V. In addition, bandgap measurements confirmed the improved conductivity characteristics with graphene oxide doping. Since this improvement in electro-optical properties is associated with the reduction process due to graphene oxide doping, X-ray photoelectron spectroscopy analysis was performed to assess the intensity change of each element. Based on these observations, hybrid thin films doped with graphene oxide emerge as promising candidates for next generation thin film.

Evaluating Free Thermal Expansion and Glass Transition of Ultrathin Polymer Films on Heated Liquid.

Thermomechanical properties of ultrathin films are crucial for fabrication and use of reliable thin electronic devices. Due to the lack of precise measurement techniques, the thermal deformation behavior of ultrathin films has not yet been clarified. Here, we propose a film on heated liquid (FOHL) method to simultaneously measure the coefficient of thermal expansion (CTE) and glass transition temperature (Tg) of multiple ultrathin polymer films. Free thermal expansion of thin films without substrate interaction can be guaranteed when the thin films are afloat on a liquid surface. To investigate the thermal behavior in a wide temperature range, glycerol is adopted as a thermally stable heating platform owing to its high boiling point of 290 °C. The thin films are transferred onto the glycerol surface from the water surface using the hygroscopic properties of glycerol. Highly accurate and high-throughput thermal strain measurement is achieved using three-dimensional digital image correlation (3D-DIC). The thermomechanical properties of ultrathin polystyrene thin films of various thicknesses (25-400 nm) are precisely characterized utilizing the FOHL and 3D-DIC method.

Metal-organic decomposed lanthanum cerium oxide thin films: A study of chemical and surface properties

Lanthanum cerium oxide thin films have been deposited on n-type (100) silicon wafers using the spin coating technique. The post-deposition annealing was performed over spin-coated films. The compositional studies were conducted by performing Fourier transform infrared spectroscopy, Energy dispersive X-ray spectroscopy, and X-ray diffraction. Ellipsometry was used to determine the thickness and atomic force microscopy was performed to understand the surface morphology of the deposited thin films. The effect of rapid thermal annealing at different temperatures over the structural and chemical properties of the LaCeO2 thin films was observed. The FTIR spectra show the formation of silicates at the interface of the oxide and semiconductor, while XRD results show that the films become crystalline with increased annealing temperature. The refractive index was observed to be reduced with an increase in the annealing temperature and a minor reduction in the physical thickness as per the sample standard deviation of 0.2981[Formula: see text]nm.

Physiochemical and electrical activities of nano copper oxides synthesised via hydrothermal method utilising natural reduction agents for solar cell application

Abstract The aim of this study is to explore the potential compatibility of copper oxide nano-powders synthesised via hydrothermal method for solar cell applications by triggering a reaction between copper acetate and various reducing agents derived from natural resources, including Arabic gum, molasses, starch, and vinegar. X-ray diffraction analysis revealed the crystalline phases of the synthesised materials, indicating the successful synthesis of copper oxide material, which was confirmed by identifying patterns that matched specific copper oxide phases. Fourier transform infrared spectroscopy was employed to analyse the molecular vibrations and chemical compounds present in the reducing agents. The reducing properties of the selected materials and their capacity to convert copper acetate into copper oxide were validated. Field-emission microscopy and transmission electron microscopy analyses of the synthesised copper oxide nanoparticles (NPs) revealed variations in particle size and morphology. These variations were dependent on the particular reducing agent utilised during synthesis. Moreover, the carrier concentration, mobility, and resistivity were evaluated as the electrical properties of the spin-coated copper oxide thin films. Hall effect analysis determined that the choice of reducing agent significantly influenced the carrier concentration (n) and mobility (µ) of the films. Remarkably, nano copper oxide films synthesised using starch exhibited irregular spherical grains with porous surfaces. Starch-synthesised samples showed the highest conductivity of n = 1.2 × 1019 cm−3 when compared with those synthesised with other reducing agents. This suggests that the porous surfaces in the starch-synthesised films may have contributed to their enhanced conductivity compared to films synthesised with alternative reducing agents. In summary, the findings emphasised the influence of the reducing agent on the size, morphology, and electrical conductivity of the copper oxide NPs.

Cu-doped NiO thin film's structural, optical, and electrical properties and its negative absorption behaviour in the Infra-Red region

NiO undoped and Cu-doped thin films on FTO-coated glass (fluorine-doped tin oxide) are prepared by employing the sol-gel spin coating method. The Cu-doping effect was observed in all the characterized reports such as absorption, transmittance, field emission scanning electron microscope (FESEM), Grazing Incidence X-ray Diffraction (GIXRD), photoluminescence (PL), Raman spectra, current-voltage measurement (IV), and X-ray photoelectron spectroscopy (XPS). Enhancement in electrical conductivity due to Cu doping and IR illumination has been found. Band gap can also be tuned by varying doping concentrations. One new phenomenon called negative absorption (NA) has been found while investigating the optical properties in the infrared (IR) region for both undoped and Cu-doped NiO on the FTO substrate, which opens a new door for advanced research. The multifarious properties of NiO thin films offer various applications in many different fields.

Effect of annealing process on structural and optical properties of Au-doped thin films (NiO:WO3) fabricated by PLD technique

Effect of annealing process on structural and optical properties of Au-doped thin films (NiO:WO3) fabricated by PLD technique

Perspective on the photochromic and photoconductive properties of Rare-Earth Oxyhydride thin films

Rare-Earth oxyhydrides (REH3-2xOx) are characterized by photodarkening when illuminated by photons having an energy exceeding that of the band gap. We propose that the film is segregated in hydrogen rich and hydrogen poor areas. Upon illumination, the excited electrons reduce the three-valent cations inducing an insulator to metal transition in the hydrogen rich entities. These small metallic oxyhydride clusters are responsible for the enhanced optical absorption. In the surrounding semiconductor matrix the photoexcitation induces a transition from p to n-type conductivity. This persistent photoconductivity is due to trapping of the holes by hydride ions. As a result, the Fermi level rises above the conduction band inducing a Burstein-Moss effect and a large increase in the conductivity.

Электрофизические и температурные характеристики тонких слоёв квантовых точек Ag2S

This paper presents a study of the electrical properties of colloidal silver sulfide quantum dots thin films (Ag2S/SiO2 QDs) and silver sulfide quantum dots decorated with Au plasmon nanoparticles (Ag2S/SiO2/Au QDs). A study of the conductivity temperature dependences was carried out in the temperature range from 300 to 360 K. The activation energy values were obtained from linear approximations of the current-voltage characteristics in Arrhenius coordinates. It has been shown that decorating Ag2S/SiO2 QDs with Au plasmon nanoparticles leads to an increase in the band gap from 0.29 to 0.89 eV. In this work, the ideality factor is calculated and the main conductivity mechanisms of the presented thin-film structures are determined. It has been shown that decorating Ag2S/SiO2 QDs with Au plasmon nanoparticles leads to a change in the conductivity type. According to the Mott-Gurney model, the charge carriers mobility is calculated.

Investigations of In2O3 Added SiC Semiconductive Thin Films and Manufacture of a Heterojunction Diode

This study involved direct doping of In2O3 into silicon carbide (SiC) powder, resulting in 8.0 at% In-doped SiC powder. Subsequently, heating at 500 °C was performed to form a target, followed by the utilization of electron beam (e-beam) technology to deposit the In-doped SiC thin films with the thickness of approximately 189.8 nm. The first breakthrough of this research was the successful deposition of using e-beam technology. The second breakthrough involved utilizing various tools to analyze the physical and electrical properties of In-doped SiC thin films. Hall effect measurement was used to measure the resistivity, mobility, and carrier concentration and confirm its n-type semiconductor nature. The uniform dispersion of In ions in SiC was as confirmed by electron microscopy energy-dispersive spectroscopy and secondary ion mass spectrometry analyses. The Tauc Plot method was employed to determine the Eg values of pure SiC and In-doped SiC thin films. Semiconductor parameter analyzer was used to measure the conductivity and the I-V characteristics of devices in In-doped SiC thin films. Furthermore, the third finding demonstrated that In2O3-doped SiC thin films exhibited remarkable current density. X-ray photoelectron spectroscopy and Gaussian-resolved spectra further confirmed a significant relationship between conductivity and oxygen vacancy concentration. Lastly, depositing these In-doped SiC thin films onto p-type silicon substrates etched with buffered oxide etchant resulted in the formation of heterojunction p-n junction. This junction exhibited the rectifying characteristics of a diode, with sample current values in the vicinity of 102 mA, breakdown voltage at approximately −5.23 V, and open-circuit voltage around 1.56 V. This underscores the potential of In-doped SiC thin films for various semiconductor devices.

Effects of Postdeposition Annealing on the Electrical Properties of Cu2O/4H–SiC PiN Diodes

Copper oxide (Cu2O) is a promising p‐type material owing to its high absorption coefficient, suitable bandgap width, chemical stability, nontoxicity, and abundance. In this study, the effect of postdeposition annealing (PDA) on the electrical properties of Cu2O thin films deposited on silicon carbide (SiC) substrates is investigated. The films are subjected to PDA using radio‐frequency sputtering at various temperatures in air. During PDA, the Cu2O films are maintained at <300 °C and transitioned to cupric oxide (CuO) at 400 °C. The as‐deposited Cu2O film exhibits a low oxidation peak (Cu2+), whereas the phase‐transformed CuO films exhibit a higher binding energy with the emergence of satellite peaks. The rectification ratios of the Cu2O device annealed at 300 °C and CuO device annealed at 400 °C are determined as 2.02 × 107 and 1.01 × 105, respectively, denoting the substantial enhancement of approximately 55.04 for the Cu2O/SiC device and degradation of approximately 0.28 for the CuO/SiC device relative to their non‐annealed counterparts. Therefore, in this study, the significant improvement in the performance of Cu2O thin films with the meticulous deposition control of potential p‐type materials, such as Cu2O and CuO, for high‐throughput and low‐cost electronic applications is demonstrated.

Exploring the Post-Annealing Influence on Stannous Oxide Thin Films via Chemical Bath Deposition Technique: Unveiling Structural, Optical, and Electrical Dynamics

Stannous oxide (SnO2) thin films have garnered significant attention for their promising applications in various electronic and optoelectronic devices. In this study, we investigate the impact of post-annealing on the structural, optical, and electrical properties of stannous oxide thin films deposited using the chemical bath deposition (CBD) technique. The thin films were prepared on a Borosilicate glass substrate, followed by a controlled annealing process to enhance their performance. Structural analysis was conducted using techniques such as X-ray diffraction (XRD) to examine the cubic crystalline structure and the crystallite size increase induced by post-annealing. The results revealed alterations in grain size from the SEM and the purity of samples confirmed from EDX results. The optical properties of the Stannous oxide thin films were examined using UV-Vis spectroscopy. The optical absorption and bandgap characteristics were analyzed to understand how post-annealing influences the optical behavior of the thin films. Where the optical absorption was 320nm and the bandgap ranges were 3.86eV to 3.83eV. Furthermore, the electrical properties of the thin films were evaluated semiconducting nature, and conductivity increased with rising post-annealing. The findings from this study contribute to the understanding of the role of post-annealing in tailoring the properties of Stannous oxide thin films. The optimization of structural, optical, and electrical characteristics is crucial for their successful integration into electronic and optoelectronic devices.