Comparative studies on the morphological, structural and optical properties of NiO thin films grown by vacuum and non-vacuum deposition techniques

The structural and optical characteristics of Nickel oxide thin films (NiOTF) formed on the soda-lime glass substrate (SLG) under vacuum and non-vacuum conditions are investigated in this work. The difference between RFMS (Radio Frequency Magnetron Sputtering; vacuum) and SP (spray pyrolysis; non-vacuum) was helpful in the development of NiOTF. Deposited films data for this study were characterized by using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), scanning probe microscopy (SPM), and optical spectrophotometer. Structural studies disclosed that NiOTF developed via RFMS technique was more uniform with large crystals and lower surface roughness in contrast to that of developed via SP technique. Transmittance spectrum divulged that the transmittance of spray pyrolyzed NiO films are ~10% less than that of ones produced by RFMS. Urbach energy analysis of NiOTF developed by RFMS and SP affirmed the findings of structural studies.

Thin Films Growth of SnO_2:F/CdS/CdTe, and Studies of Their Physical and Optical Properties using Spray Pyrolysis Techniques

Fluorine doped tin oxide, Cadmium Sulphide and Cadmium Telluride thin films have been deposted on Soda Lime glass substrate at respectively by spray pyrolysis (SP) technique and are important semiconductor materials in optoelectronic devices such as optical sensors, light-emitting diodes, transistors and photovoltaic cells. thin films were characterized by various techniques such as X-ray diffraction, SEM and optical studies. X-ray diffraction measurements show that the deposited was found to be of cassiterite type with tetragonal rutile structure, observation of peaks of different planes on an X-ray diffraction graph of thin film showed that film obtained were cubic structure. The main peak value of thin film is seen at , which is the characteristic peak of the compound and the film structure was obtained at the major peak indicating the preferred orientation of films along direction. This confirms the formation of thin film, with (111) as the strongest preferred plane of orientation. The surface morphology of the thin films was analysed by scanning electron microscopy (SEM). The optical energy band gap of thin films are determine The results showed that the prepared FTO, CdS and CdTe films can be used in solar energy applications.

Flower-like Na2O nanotip synthesis via femtosecond laser ablation of glass

The current state-of-the-art in nanotip synthesis relies on techniques that utilize elaborate precursor chemicals, catalysts, or vacuum conditions, and any combination thereof. To realize their ultimate potential, synthesized nanotips require simpler fabrication techniques that allow for control over their final nano-morphology. We present a unique, dry, catalyst-free, and ambient condition method for creating densely clustered, flower-like, sodium oxide (Na2O) nanotips with controllable tip widths. Femtosecond laser ablation of a soda-lime glass substrate at a megahertz repetition rate, with nitrogen flow, was employed to generate nanotips with base and head widths as small as 100 and 20 nm respectively, and lengths as long as 10 μm. Control of the nanotip widths was demonstrated via laser dwell time with longer dwell times producing denser clusters of thinner nanotips. Energy dispersive X-ray analysis reveals that nanotip composition is Na2O. A new formation mechanism is proposed, involving an electrostatic effect between ionized nitrogen and polar Na2O. The synthesized nanotips may potentially be used in antibacterial and hydrogen storage applications. PACS: 81 Materials science; 81.07.-b nanoscale materials and structures: fabrication and characterization; 81.16.-c methods of micro- and nanofabrication and processing

Flower-like Na2O nanotip synthesis via femtosecond laser ablation of glass

The current state-of-the-art in nanotip synthesis relies on techniques that utilize elaborate precursor chemicals, catalysts, or vacuum conditions, and any combination thereof. To realize their ultimate potential, synthesized nanotips require simpler fabrication techniques that allow for control over their final nano-morphology. We present a unique, dry, catalyst-free, and ambient condition method for creating densely clustered, flower-like, sodium oxide (Na2O) nanotips with controllable tip widths. Femtosecond laser ablation of a soda-lime glass substrate at a megahertz repetition rate, with nitrogen flow, was employed to generate nanotips with base and head widths as small as 100 and 20 nm respectively, and lengths as long as 10 μm. Control of the nanotip widths was demonstrated via laser dwell time with longer dwell times producing denser clusters of thinner nanotips. Energy dispersive X-ray analysis reveals that nanotip composition is Na2O. A new formation mechanism is proposed, involving an electrostatic effect between ionized nitrogen and polar Na2O. The synthesized nanotips may potentially be used in antibacterial and hydrogen storage applications. PACS: 81 Materials science; 81.07.-b nanoscale materials and structures: fabrication and characterization; 81.16.-c methods of micro- and nanofabrication and processing

Flower-like Na2O nanotip synthesis via femtosecond laser ablation of glass

The current state-of-the-art in nanotip synthesis relies on techniques that utilize elaborate precursor chemicals, catalysts, or vacuum conditions, and any combination thereof. To realize their ultimate potential, synthesized nanotips require simpler fabrication techniques that allow for control over their final nano-morphology. We present a unique, dry, catalyst-free, and ambient condition method for creating densely clustered, flower-like, sodium oxide (Na2O) nanotips with controllable tip widths. Femtosecond laser ablation of a soda-lime glass substrate at a megahertz repetition rate, with nitrogen flow, was employed to generate nanotips with base and head widths as small as 100 and 20 nm respectively, and lengths as long as 10 μm. Control of the nanotip widths was demonstrated via laser dwell time with longer dwell times producing denser clusters of thinner nanotips. Energy dispersive X-ray analysis reveals that nanotip composition is Na2O. A new formation mechanism is proposed, involving an electrostatic effect between ionized nitrogen and polar Na2O. The synthesized nanotips may potentially be used in antibacterial and hydrogen storage applications. PACS: 81 Materials science; 81.07.-b nanoscale materials and structures: fabrication and characterization; 81.16.-c methods of micro- and nanofabrication and processing

A Highly Efficient and Stable Photocatalyst; N-Doped ZnO/CNT Composite Thin Film Synthesized via Simple Sol-Gel Drop Coating Method

The thin film of N-doped ZnO/CNT nanocomposite was successfully fabricated on soda lime glass substrate by a simple sol-gel drop-coating method. The structural, morphological, chemical, and optical properties of as prepared samples were characterized by a variety of tools such as X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), Fourier Transform Infrared spectroscopy (FT-IR), and UV-visible spectroscopy. The hexagonal crystalline structure was confirmed from XRD measurement without any other impurity phase detection in samples. The N-doped ZnO/CNT composite showed excellent photo-catalytic activity towards cationic methylene blue (MB) dye degradation with 100% removal rate under UV light irradiation as compared to N-doped ZnO (65%) and pure ZnO (47.36%). The convincing performance has also been observed for the case of visible light irradiation. The enhancement of that photocatalytic activity might be due to narrowing the band gap as well as the reduction of electron–hole pair recombination in ZnO matrix with the incorporation of dopant nitrogen and CNT. It is assumed from the obtained results that N-doped ZnO/CNT nanocomposite thin film can be employed as an economically achievable and ecofriendly method to degrade dye with UV and visible light irradiation. Additionally, density functional theory (DFT) calculations were applied to explore the effect of N-doping on electronic structure of ZnO. The computational study has supported the experimental results of significant band gap contraction, which leads to the maximum absorption towards higher wavelength and no appreciable change of lattice parameters after doping. A conceivable photocatalytic mechanism of N-doped ZnO/CNT nanocomposite has been proposed as well.

Microstructural and Optical Characterization of Heterostructures of ZnS/CdS and CdS/ZnS Synthesized by Chemical Bath Deposition Method

ZnS/glass and CdS/glass single layers and ZnS/CdS and CdS/ZnS heterojunction thin films were deposited by the chemical bath deposition method using zinc acetate and cadmium acetate as the metal ion sources and thioacetamide as a nonmetallic ion source in acidic medium. Na2EDTA was used as a complexing agent to control the free cation concentration. The single layer and heterojunction thin films were characterized with X-ray diffraction (XRD), a scanning electron microscope (SEM), energy dispersive X-ray (EDX), and a UV-VIS spectrometer. The XRD patterns of the CdS/glass thin film deposited on the soda lime glass substrate crystalized in the cubic structure with a single peak along the (111) plane. The ZnS/CdS heterojunction and ZnS/glass single layer thin films were crystalized in the hexagonal ZnS structure. The CdS/ZnS heterojunction thin film is nearly amorphous. The optical analysis results confirmed single band gap values of 2.75 eV and 2.5 eV for ZnS/CdS and CdS/ZnS heterojunction thin films, respectively. The CdS/glass and CdS/ZnS thin films have more imaginary dielectric components than the real part. The optical conductivity of the single layer and heterojunction films is in the order of 10 15 1/s. The optical study also confirmed refractive index values between 2 and 2.7 for ZnS/glass, ZnS/CdS, and CdS/ZnS thin films for incident photon energies between 1.2 eV and 3.8 eV. The surface morphology studies revealed compacted spherical grains covering the substrate surfaces with few cracks on ZnS/glass, ZnS/CdS, and CdS/glass and voids on CdS/ZnS thin films. The EDX result confirmed nearly 1 : 1 metallic to nonmetallic ion ratio in the single-layered thin films and the dominance of Zn ion over Cd ion in both ZnS/CdS and CdS/ZnS heterojunction thin films.

Structural Origin of Magnetotransport Properties in APCVD Deposited Single and Bi-Layer Tin Oxide Thin Films

Tin oxide (SnO2) thin films, undoped single-layer and fluorine doped / undoped bilayer were deposited by Atmospheric Pressure Chemical Vapour Deposition (APCVD) at soda-lime glass substrate at two different temperatures (590°C and 610°C). Transport properties examined by impedance spectroscopy, DC resistivity, Hall effect and magnetoresistance measurements are correlated with structural properties examined by Scanning Electron Microscopy, Grazing Incidence X-ray Diffraction (GIXRD) and Time-of-flight Elastic Recoil Detection Analysis (TOF-ERDA). Results suggest that charge transport in the obtained samples is dominated by scattering at neutral impurities and can be correlated with preferred orientation (texture coefficient) presented in prepared samples.

Effects of Radio-Frequency Sputtering Power on Low Temperature Formation of MoS2 Thin Films on Soda-Lime Glass Substrates

For the realization of the economical and reliable fabrication process of molybdenum disulfide (MoS2) layers, MoS2 thin films were directly formed a on soda-lime glass substrate by RF sputtering and subsequent rapid thermal annealing (RTA) at a temperature range of 400–550 °C. Using scanning electron microscopy and atomic force microscopy, it was possible to investigate more stable surface morphologies of MoS2 layers at lower RF sputtering powers irrespective of the RTA temperature. Even at an RTA temperature of less than 550 °C, the Raman exhibited more distinct E12g and A1g peaks for the MoS2 layers sputtered at lower RF powers. The X-ray photoelectron spectroscopy results revealed that more distinct peaks were observed at a higher RTA temperature, and the peak positions were moved to higher energies at a lower RF sputtering power. Based on the Hall measurements, higher carrier densities were obtained for the MoS2 layers sputtered at lower RF powers.

Bioelectronics-on-a-chip for Cardiomyoblast Proliferation Enhancement Using Electric Field Stimulation

Background:Cardiomyoblast generation from conventional approaches is laborious and time-consuming. We present a bioelectronics on-a-chip for stimulating cells cardio myoblast proliferation during culture. Method:The bioelectronics chip fabrication methodology involves two different process. In the first step, an aluminum layer of 200 nm is deposited over a soda-lime glass substrate using physical vapor deposition and selectively removed using a Q-switched Nd:YVO4laser to create the electric tracks. To perform the experiments, we developed a biochip composed of a cell culture chamber fabricated withpolydimethylsiloxane (PDMS) with a glass coverslip placed over the electric circuit tracks.By using such a glass coverslip we avoid any toxic reactions caused by electrodes in the culture or may be degraded by electrochemical reactions with the cell medium, which is crucial to determine the effective cell-device coupling. Results:The chip was used to study the effect of electricfield stimulation of Rat ventricular cardiomyoblasts cells (H9c2). Results shows a remarkable increase in the number of H9c2 cells for the stimulated samples, where after 72 hours the cell density double the cell density of control samples. Conclusions:Cell proliferation of Rat ventricular cardiomyoblasts cells (H9c2) using the bioelectronics-on-a-chip was enhanced upon the electrical stimulation. The dependence on the geometrical characteristics of the electric circuit on the peak value and homogeneity of the electric field generated are analyzed and proper parameters to ensure a homogeneous electric field at the cell culture chamber are obtained. It can also be observed a high dependence of the electric field on the geometry of the electrostimulator circuit tracks and envisage the potential applications on electrophysiology studies, monitoring and modulate cellular behavior through the application of electric fields