Glass Slide Substrates Research Articles

Low-Temperature Synthesis of Vanadium Dioxide Thin Films by Sol-Gel Dip Coating Method

The vanadium dioxide (VO2) thin films were synthesized by sol-gel dipping on a glass slide substrate at low temperature of 500°C in a vacuum tube furnace at a pressure of 2 × 10−3 mbar by 2-step calcination without an intermediate gas purging. Synthesis conditions, including temperature, vacuum pressure, and calcination steps in the vacuum tube furnace, were investigated to find the optimum condition that promoted the formation of VO2 phase. It was found that the 2nd calcination step was very important in realizing the monoclinic vanadium dioxide (VO2 (M)). The results of the valence electron analysis revealed the outstanding phase of VO2 and a small amount of V2O5 and V2O3 phases. The small crystallites of the VO2 were homogeneously distributed on the surface, and the grain was of an irregular shape of ∼220−380 nm in size. The film’s thickness was in a range of 69−74 nm. The film exhibited a metal-to-insulator transformation temperature of ∼68oC and good thermochromic property. Visible optical transmittance remained at ∼40−50% when the sample’s temperature changed from 25 to 80°C for a near infrared (NIR) region.

Heterogeneous integration of AuNRs monolayer with MoS2 film assembled for highly efficient surface-enhanced Raman scattering and significant in improvement electrical conductivity

Integration techniques that combine substrates, metals, and semiconductor components were developed to achieve excellent mechanical compliance and electrical performance simultaneously for wearable electronics. Herein, heterogeneous integration of AuNRs monolayer with MoS2 film on glass slide (or polyethylene terephthalate, PET) substrate had been fabricated into Janus gold nanorods/molybdenum disulfide (AuNRs-MoS2) film with large-area metamaterials by a modified self-assembly methods. Janus AuNRs-MoS2 film showed the high efficient surface-enhanced Raman scattering and significantly enhanced electrical conductivity. The SERS intensity of AuNRs-MoS2 film was obviously higher than that of AuNRs film and MoS2 film due to the densely packed nanoparticles. In addition, the conductivity of Janus AuNRs/MoS2 film increased rapidly as the thickness of MoS2 increased. The conductivity of Janus AuNRs/MoS2 film on PET was obviously higher than that of film on glass slide with similar thickness of MoS2 film. This work provides a platform to inspire novel bilayer approaches with surface enhanced properties.

Effect of different pH values on growth solutions for the ZnO nanostructures

In this study, high quality zinc oxide (ZnO) nanostructures were synthesized on glass slide substrates using modified chemical bath deposition (M-CBD) method at low temperature. Through the M-CBD technique the air bubbles will be injected into aqueous growth solution. The RF magnetron sputtering method was utlized to grow ZnO seed layer on the glass substrates. The effect of different pH values of aqueous growth solution on the morphology, elemental chemical composition, crystal structural and the optical properties of ZnO nanostructures have been investigated using field emission-scanning electron microscopy (FE-SEM), Energy dispersive analysis (EDX), X-ray diffraction (XRD), and UV-Visible Spectrometer, respectively. It was observed that altering pH values from acidic to alkaline (basic) by using ammonia solution (NH3) induced the significant change in morphology from nanorods like ZnO to nano-amber flush rose like ZnO structures. Furthermore, increased pH values had an effect on the influence intensity of the preferred orientation plane (002) and average transmittance spectrum. Whilst the absorption band edge has been shifted to a lower energy region due to the quantum size effect. It was also found that the crystal size fluctuated between 36.30 nm and 84.33 nm with a different values of pH from 6.7 to 12. The ZnO synthesized at 6.7 of pH provided the best results regarding the high aspect ratio,structural and optical properties. At this pH value, ZnO growth revealed the nanorod structure with small diameters, size and a higher energy band gap value.

Optimization and characterization of SILAR synthesized ZnO nanorods for UV photodetector sensor

In the current research, zinc oxide (ZnO) nanorods (NRs) have been grown upon glass-slide substrates by employing the effective chemical bath deposition (CBD) method at low-temperature. ZnO seed-layer has been coated over the whole substrates by using very simplicity successive ionic-layer adsorption and reaction (SILAR) approach. The impact of the four different SILAR process cycle for ZnO seed-layer deposition on the characteristic of ZnO NRs have been investigated. The surface morphological, structural, optical properties of the produced ZnO NRs have been studied using several techniques for different SILAR process cycles. Also, the high-quality UV photodetector (PDs) based on ZnO NRs at different SILAR process cycles have been successfully fabricated by applying bias voltage in range of (-5 V to 5 V). The results indicated that the variation of SILAR process cycles have the large and significant impact on the morphological, structural, and optical properties of ZnO NRs. The average size and length of fabricated ZnO NRs were increased with increases the SILAR cycles in the range of 32−98 nm and 291−1210 nm, respectively. The large aspect ratio was noted for ZnO NRs formed at 15 SILAR cycles about 14.93. The growth rate and crystal size of ZnO NRs were increases with increases the SILAR cycles in the range of 1.161–6.722 nm/min and 28.9–94.24 nm/min, respectively. All the samples display a dominant peak at wavenumber of 436.5 cm−1 which is attributed to the E2 active mode and characteristic of the hexagonal phase of ZnO NRs. The energy gap of ZnO NRs was decreased from 3.25 eV to 3.23 eV as the SILAR cycles increases from 5 cycles to 20 cycles. The overall ultraviolet (UV) emission peak centered at 380 nm is found to correlate to near-band emissions (NBE). The ZnO NRs based UV-detector displays repeatable characteristics with a peak photoresponse of 116.6 μA. The UV-sensor based ZnO NRs grown at 15 SILAR process cycles at 5 V bias voltage shows optimal performance responsivity, high photosensitivity, low dark current, quick rise and recovery times were 0.5477 A/W, 3573.57 %, 3.1743 μA, 1.04259 s, and 0.3046 s, respectively.

Magnetic Phase Transition without Heat Treatment of the as-Deposited Iron Oxide Nanoparticulate Films Prepared by Sparking Process under External Magnetic Fields

In this paper, the effect of external magnetic fields on morphology, structural and magnetic properties of the as-deposited iron oxide nanoparticulate (NP) films by the sparking process was investigated. The small and uniform size of iron oxide nanoparticles was deposited on a glass slide substrate by sparking off the iron wires with different external magnetic fields under atmospheric pressure and room temperature. The results showed the roughness and the agglomerated particles of the as-deposited films increased with increasing the external magnetic field due to magnetic and Lorentz forces. The magnetic phase was transformed from maghemite (γ-Fe2O3) to magnetite (Fe3O4) after sparking under the external magnetic field from 0 mT (without field) to 50 and 100 mT. Moreover, the external magnetic field not only affects the magnetic phase transition but also has a direct effect on the energy band gap and magnetization of the films without heat treatment.

Characterization of Thin Films Deposited from Benzene Using Microwave Plasma Polymerization

Microwave plasma enhanced chemical vapor deposition (MWPECVD) is a cheap and easy method for the modification of materials surfaces to enhance some required property. In this study, benzene as a monomer was deposited on both Aluminum alloy (2024-T3) and glass slide substrates at several pressures and deposition times using MWPECVD. The chemical structure and surface properties of as-grown thin films were analyzed on glass using FTIR and NMR. It is found that benzene rings are not fully preserved in the film structure. Some benzene rings were converted to saturated alcohol and/or ester functional groups in the crosslinked film structure. The corrosion resistance of aluminum alloy substrates both bare and covered with plasma polymerized thin films was carried out by potentiodynamic polarization measurements in standard 3.5% NaCl solution at room temperature. The benzene deposited film was found to be not fully suitable for protection of aluminum substrate against corrosion. The only film that stayed intact post the corrosion measurement is that for the deposition condition of 30 mtorr for 90 minutes. The change in the processing parameters seemed to have a strong influence on the film protective ability. SEM was used to study the surface morphology of deposited films on aluminum. It is found that the polymerized film roughness decreases with increasing monomer pressure and deposition time. Adhesion test done on films deposited on glass showed that the best adhesion occurs for deposition condition of 30 mtorr for 90 minutes and poor adhesion occurred at 7 and 9 mtorr for 90 minutes.

Synthesis of lead oxide thin films by using physical vapor deposition technique

In this study, the lead oxide thin films were synthesized upon the glass slide substrate by using the physical vapor deposition (PVD) technique. The molybdenum boat was used to heat the high purity lead (Pb) powder with 5 × 10 −5 mbar vacuum pressure of the PVD chamber. The morphological, structural, and optical properties have been examined and characterized by employing different characterizations techniques. The results found that the crystal size and interplanar distance of lead oxide thin film were about 1.695 nm and 3.55 Å, respectively. The lead oxide thin film has high average transmittance in the visible region which was about (∼80%) and low average transmittance in the UV region. Also, the energy band gap (E g ) of the deposited lead oxide thin film was 2.35 eV.

Synthesis and Characterizations of ZnO Thin Films Grown by Physical Vapor Deposition Technique

In the current study, Zinc oxide (ZnO) thin films have been synthesized over the whole the glass-slide substrate by utilizing the physical vapor deposition (PVD) technique. The Zinc (Zn) seed layer was deposited by heating the high purity Zn powder by using a molybdenum (Mo) boat at 37.503×10-3 Torr vacuum pressure of the PVD chamber. The ZnO thin films were fabricated by oxidation of the Zn seed layer coated glass-slide substrate at 400 °C. The morphological, chemical compositions, crystal quality, structural and optical properties of fabricated ZnO thin film were characterized and studied utilizing several characterization techniques. The results found that the high distribution density, homogenous, uniform, and high-quality ZnO thin film was grown over the entire substrate. The synthesized ZnO thin film with a thickness of 130 nm was grown with high purity and polycrystalline hexagonal-Wurtzite phase of ZnO. The sharp, and dominant diffraction peak was observed at peak position 34.3375 along (002) plane and c-axis. The investigated crystal size, dislocation density, and interplanar spacing were about 13.33 nm, 5.63×10-5 A°, and 2.609 A°, respectively. Also, UV-visible spectroscopy results show the high transmittance and low absorbance in the visible (Vis.) region and were about 90%, and the transmittance decreases sharply near the UV region at a wavelength around 383 nm. Besides, obtained the energy band-gap (Eg) was about 3.24 eV.

Study of the semiconducting properties of Cu2ZnSnS4 thin films grown by ultrasonic spray pyrolysis of water-dissolved precursors

Cu2ZnSnS4 (CZTS) thin films were deposited on glass-slide substrates by ultrasonic spray pyrolysis at the substrate temperatures in the 330–420 °C range, using water–ethanol solutions containing CuCl2–H2O, ZnCl2, SnCl2, and (NH2)2CS (thiourea). After being deposited, CZTS films were annealed under vacuum and then characterized in regarding their structural and optical properties. The X-ray diffraction and Raman spectroscopy studies indicated that CZTS thin films with kesterite as predominant phase could be obtained. The X-ray diffraction patterns of all deposited samples displayed diffraction peaks corresponding to the planes (112), (220), and (312) of kesterite CZTS and diffraction peaks belonging to phases other than CZTS were apparently undetectable for the X-ray technique. Furthermore, their Raman spectra were featured for a widely structured Raman band in the 200–400 cm−1 wavenumber area. After being deconvoluted, Raman peaks belonging only to kesterite CZTS were revealed. However, a further analysis of the UV–Vis absorbance spectra indicated all our films strongly absorbs in this spectral region. In the low photon energy region (< 1.5 eV), Tauc plots revealed electron transitions with characteristic energy values in the 1.15–1.34 eV range, which could be attributed at the presence of tetragonal Cu2SnS3 and point defects (VS and VZn) into CZTS. All prepared CZTS films display the p-type conductivity as verified by Hall measurements.

Profiling of cured residue of solvent-based adhesives by attenuated total reflectance-Fourier transform infrared spectroscopy with chemometrics for forensic investigation.

Abuse of solvent-based adhesives jeopardizes world population, especially the young generation. Adhesive-related exhibits encountered in forensic cases might need to be determined if they could have come from a particular source or to establish link between cases or persons. This study was aimed to discriminate solvent-based adhesives, especially to aid forensic investigation of glue sniffing activities. In this study, thirteen brands with three samples each, totaling at 39 adhesive samples, were analyzed using attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy followed by chemometric methods. Experimental output showed that adhesive samples utilized in this study were less likely to change in their ATR-FTIR profiles over time, at least up to 2months. No interference from plastic materials was noticed based on ATR-FTIR profile comparison. Physical examination could differentiate the samples into two groups, namely contact adhesives and cement adhesives. A principal component analysis-score linear discriminative analysis (PC-score LDA) model resulted in 100% and 98.6% correct classification in discriminating the two groups of adhesive samples, forming seven discriminative clusters. Test set with adhesive samples applied glass slide and plastic substrates also demonstrated a 100% correct classification into their respective groups. As a conclusion, the method allowed for discrimination of adhesive samples based on the spectral features, displaying relationship among samples. It is hoped that this comparative information is beneficial to trace the possible source of solvent-based adhesives, whenever they are recovered from a crime scene, for forensic investigation.

Enhanced Optical and Electrical Properties of Ti Doped In&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; thin Films Treated by Post-deposition Electron Beam Irradiation

Transparent and conductive Ti doped In&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; (TIO) films were prepared on slide glass substrate using a radio frequency (RF) magnetron sputter and then subjected to Transparent and conductive Ti doped In&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; (TIO) films were prepared on a glass slide substrate using radio frequency (RF) magnetron sputter. The film surface was then subjected to intense electron beam irradiation, to study the influence of incident energy on the visible transmittance and electrical resistivity of the films. All x-ray diffraction plots exhibited some diffraction peaks of the cubic bixbyite In&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; (222), (400), (332), (431), (440), and (444) planes regardless of the electron irradiation energy, while the characteristic diffraction peak for crystalline TiO&lt;sub&gt;2&lt;/sub&gt; did not appear even when irradiated at 1500 eV. In atomic force microscope analysis, the surface roughness of the as deposited TIO films was found to be 0.63 nm. As the electron irradiation energy was increased up to 1500 eV, the root mean square roughness decreased down to 0.36 nm. The films electron irradiated at 1500 eV showed higher visible transmittance of 83.2% and the lower resistivity of 6.4 × 10&lt;sup&gt;-4&lt;/sup&gt; Ωcm compared to the other films. From the electrical properties and optical band gap observation, it is supposed that the band gap shift is related to the carrier density. The band gap enlarged from 4.013 to 4.108 eV, along with an increase in carrier density from 9.82 × 10&lt;sup&gt;19&lt;/sup&gt; to 3.22 × 10&lt;sup&gt;20&lt;/sup&gt; cm&lt;sup&gt;-3&lt;/sup&gt;.

Tuning silica nanophotonics based on fluorescence resonance energy transfer for targeted non-classical light delivery applications

Tunable fluorescent silica nanoparticles (SiO2 NPs) with variable sizes based on fluorescence resonance energy transfer were synthesized. The SiO2 NPs were obtained by the Störber method by varying tetraethyl orthosilicate (TEOS) concentrations and with the incorporation of different concentrations of fluorescein (Fl) and rhodamine B (RhB) conjugated with 3-(aminopropyl)triethoxysilane. We thus recorded homogeneous SiO2 NPs of different sizes. By transmission electron microscopy imaging, the sizes of 200, 280, and 380 nm were determined. The Fl and RhB fluorescent dyes showed well-overlapped emission from the fluorescent energy donor to the energy acceptor with the optimal ratio of quantum yields. By static fluorescence, varied emissions were recorded according to the concentration ratio of the donor–acceptor pair. Increasing intensity values were collected with the addition of higher concentrations of the fluorescent energy donor and decreased fluorescent lifetime decays. By laser fluorescence microscopy, higher enhanced surfaces were produced in the presence of both emitters, as compared with those in the presence of mono-colored SiO2 NPs with optimal excitation with the fluorescent energy donor only. These NPs were well dispersed in polar solvents; however, due to their polar surface and size, higher interactions produced dimeric nanoaggregates. In addition, to evaluate their applications, their depositions were evaluated over modified glass slide substrates for smart light-responsive materials and over Cyanobacteria and Escherichia coli for the development of nanobiostructures with varied optical activities.

Facile fabrication and optical characterization of nanoflake aluminum oxide film with high broadband and omnidirectional transmittance enhancement

Abstract In this study, the non-lithography fabrication of nanoflake aluminum oxide (Al2O3) film with omnidirectional broadband antireflection properties was demonstrated. The nanoflake Al2O3 films on glass slide and silicon wafer substrates were sequentially prepared by reactive magnetron sputtering and surface modification with alkali-treatment and hot water treatment processes. The morphologies, chemical compositions and optical properties of the prepared samples were characterized by field-emission scanning electron microscope (FE-SEM), photoelectron spectroscopy (PES), variable angle spectroscopic ellipsometry (VASE) and UV-VIS spectrophotometry with angle-dependent transmittance measurements, respectively. The results indicated that the thickness of the sputtered Al2O3 film was a crucial parameter for the growth of nanoflake for the nanostructure formed by alkali treatment with 0.1 M of potassium hydroxide (KOH) at room temperature and hot water treatment in deionized (DI) water at 80 °C for 3 min. The best optical performance was achieved with the single nanoflake film layer, resulting in enhanced optical transmittance exceeding 90% over the broad range of visible region at wide incident angle. This facile fabrication process of the nanoflake layer was offering the potential benefits for inexpensive omnidirectional anti-reflection (AR) coating in large area.

A new efficient synthesis of CuO thin films using modified SILAR method

Due to its direct band gap and high absorption coefficient, Cupric Oxide (CuO) is widely used as an absorbent material for solar cells, yet most of the available deposition methods are expensive and complex. For this reason, this paper is concerned with the elaboration of CuO thin films using the simple and inexpensive modified successive ionic layer adsorption and reaction method, i.e., modified SILAR method. To that end, glass slide substrates and an aqueous solution of hydrated copper chloride (CuCl $$_{2}$$ ·2H $$_{2}$$ O) complexed with aqueous ammonia (NH $$ _{3} $$ ) (25–28%) were used, then the growth conditions were carefully evaluated to reduce the presence of the remaining phases other than CuO. The elaborated thin films are studied from four perspectives: (1) structural decomposition, (2) morphological decomposition, (3) chemical decomposition and (4) optical properties. It is found that the deposited films are polycrystalline and crystallized in a pure CuO monoclinic structure without any other secondary phase. Raman and X-ray photoelectron spectroscopy confirmed the pure phase obtained and the scanning electron microscopy images showed that the resulting films were dense, smooth and homogeneous. The energy dispersive X-ray spectrum and the elemental mapping scan corroborate the uniform distribution of Cu and O elements on the film surface. Furthermore, UV–visible spectra exhibited a negative correlation between optical transmission and deposition cycles—if the deposition cycles increased, optical transmission decreased similarly the optical band gap. As well as the refractive index and Urbach energy were determined. As a result, the synthesis technique is very simple and low cost, CuO thin films could be appropriate for solar cells applications.

Effect of pH treatment on the structural and optical properties of Sn6Sb10S21 thin films facilely synthesized using a spin coating method

This study aimed to examine the effect of pH value for the Sn–Sb–S solution on the growth of tin antimony sulfide (TAS) thin films facilely synthesized and deposited on fluorine-doped tin oxide or borosilicate slide glass substrates using a spin coating method. Field-emission scanning electron microscopy (FE-SEM) micrographs confirmed that some aggregated NPs, the distribution of residuals and larger-sized clusters or non-uniform surfaces of thin films on the substrate surface were significantly affected by pH alteration. XRD analysis revealed that the most intense peak of TAS thin films exhibited a monoclinic Sn6Sb10S21 crystal structure with an orthorhombic Sn5Sb2S9 phase. However, the presence of a binary Sb2S3 phase was also observed; its peak intensity gradually reduced with increasing pH value. In addition, the investigation revealed that change in the structural and optical parameters under the alteration of the pH treatment in a solution had a significant impact on the formation, nucleation and growth of the clusters with increasing residuals and non-uniformity of thin film. It could be concluded from the overall results of our demonstration that TAS thin films with adjusted pH treatment can be attributed to the growth of TAS thin films for use as window layers in solar cell devices and may have potential for use in photodetector, optical communication, and optical dispersion devices in the future.

Effect of oxygen flow rate on physical properties of Al-doped ZnO transparent conducting films prepared by reactive dc magnetron sputtering using metallic Zn:Al target

In this work, Al-doped ZnO transparent conducting thin films were prepared by a reactive dc magnetron sputtering method on slide glass substrate using single metallic Zn:Al (2 wt.% Al) target with the oxygen flow rate 1, 3, 5, 7 and 9 sccm, respectively. From XRD patterns, the films prepared at R(O2) of 1 sccm showed amorphous characteristics. In contrast, the films prepared at R(O2) of 3, 5, 7 and 9 sccm showed the preferred orientation (002) plane of hexagonal structure. Surface morphology and diameter of nanocolumns of the films were observed by AFM and FESEM. From transmittance spectra, energy gap value was found to vary between 3.24 and 3.32 eV. Electrical resistivity and Hall effect measurements were performed on the films with van der Pauw configuration. The temperature-dependent conductivity was performed in the range 20-300 K. Three types of conduction mechanisms were expected. Thermally activated band conduction at the high temperature range (250-300 K), Mott variable-range hopping (Mott-VRH) at the low temperature range (100-210 K) and Efros-Shklovskii variable-range hopping (ES-VRH) at the very low temperature range (<100 K) can be found in the films prepared with different oxygen flow rate conditions. Except for the oxygen flow rate at 5 sccm, the behavior of weakly localized electrons was observed. Then, the sets of parameters explaining the properties of localized electrons in each conduction regime were determined. The results indicated that the reactive dc magnetron sputtering using a single metallic Zn:Al (2 wt.% Al) target is suitable for TCO films since it can be easily obtained at low temperatures with good physical properties.

Effect of ultrasonic field on grain refinement and stress relaxation of Be films by thermal evaporation

The beryllium (Be) films were prepared by vacuum evaporation with ultrasound on the glass slide substrates. The Be coating mainly consists of α-Be phase independent of ultrasonic vibration, while the texture and crystallinity are affected by ultrasonic vibration. With the increasing of ultrasonic power, the surface displays polygonal grains, but the grain size decreases from 130 nm to 60 nm. The cross section views show a transition from regular columnar structure to broken columnar structure owing to the ultrasonic mechanical agitation. When ultrasonic vibration is applied, the microstructure transforms from isolated islands to bicontinuous islands in the initial stage of film growth. In addition, the residual stress of Be films changes from a tensile stress to compressive stress under the effect of ultrasonic vibration, which is closely related to the transformation of microstructure.

The Influence of Various Reactants in the Growth Solution on the Morphological and Structural Properties of ZnO Nanorods

In the current work, the effect of three different Zinc (Zn) salts as reactants precursors in the growth solution on the characteristic properties of the Zinc oxide (ZnO) nanorods (NRs) was investigated and reported. High quality hexagonal ZnO NRs have been grown on the glass-slide substrates via the chemical-bath deposition (CBD) approach at 90 ºC. The radio-frequency sputtering (RF) technique has been used to coat the 150 nm of ZnO nano-seed layer over the whole glass-slide substrates. The Field-emission scanning electron microscopy (FESEM), the Energy-dispersive characterization (EDX), and the X-ray diffraction (XRD) characterizations have been used to characterize and examination of the morphological, chemical compositional, and structural characteristics with ZnO hexagonal-wurtzite structure of the NRs. The used zinc salts were Zinc-nitrate Hexahydrate (ZNH), Zinc-acetate (ZA), and Zinc-chloride (ZC). The FESEM and XRD results indicated that the change in types of Zinc salts with Methenamine as reactants precursors in the growth (deposition) solution have a remarkable and significant impact on the surface topography (morphology) characteristics and structural characteristics of synthesized ZnO NRs. The average size and average length of the grown ZnO NRs were in the range of (91-529) nm and (1008-3189) nm, respectively. The high aspect ratio was obtained of ZnO NRs synthesized from Zinc-nitrate Hexahydrate salt and was about 11. The highest growth rate was investigated ZnO NRs synthesized from Zinc-chloride salt and was about 17.716 nm/min. The average crystalline size of synthesized ZnO nanorods was in the range (48.35-56.06) nm

Interfacial crosslinked controlled thickness graphene oxide thin-films through dip-assisted layer-by-layer assembly means

The augmentation of research in graphene based thin films has been of great interest to various current industrial stakeholders. This is mainly due to the wide scope of films applications, ranging from nanoelectronics to separation membranes. Therefore, establishing a relation between graphene based thin film key characteristics and the fabrication operating conditions is of high significance. This study entails the successful fabrication of controlled-thickness crosslinked graphene oxide (GO) thin films on inexpensive silicon-based glass slide substrates. The method of film fabrication used is the dip-assisted layer-by-layer assembly, which has an added advantage of step-control of thin film thickness, good film uniformity and continuity. The thickness was primarily tuned through the use different sized crosslinkers; a covalent based sub-nanometer sized p-phenylenediamine and an electrostatic based polyethyleneimine on an interchangeable assembly with GO. Pre film fabrication, Fourier Transform Infra-Red and X-Ray Photoelectron Spectroscopy characterizations were carried out to determine the nature of interactions between GO and the crosslinkers. Post film fabrication, scanning electron microscopy, water contact angle measurements and profilometry analysis were undertaken for film continuity, hydrophilicity and thickness measurements respectively. A strong linear trend between film thickness of the differently crosslinked films and the number of bi-layers was established.

Improved Transparent Gas Sensor Properties of Cu-Doped SnO2 Films using O2 Plasma Treatment

Cu-doped SnO2 films were deposited on glass slide substrate using an RF magnetron sputtering method. The effects of O2 partial pressures in the deposition process and post O2 plasma treatment were assessed for optical and sensing properties. O2 partial pressures from 2% to 10% were assessed. Post-plasma treatment used a 15 mL/min O2 flow, 450 °C annealing temperature and 30 min treatment time. Optical transmission spectra showed that the films deposited at higher O2 partial pressures had higher transparency and increased band gaps from 3.08 to 3.78 eV. After O2 plasma treatment, the films showed better than optical transmission. However, when the O2 partial pressure increased to 10%, the optical transmission declined slightly because the film had higher surface roughness, smaller crystals and fewer oxygens in the parent rutile tetragonal cells, enhanced the sensor response at room temperature.