Investigation of optical,structural and morphological properties of nanostructured boron doped TiO 2 thin films

Pure and different ratios (1, 3, 5, 7 and 10%) of boron doped TiO₂ thin films were grown on the glass substrate by using sol–gel dip coating method having some benefits such as basic and easy applicability compared to other thin film production methods. To investigate the effect of boron doped on the physical properties of TiO₂, structural, morphological and optical properties of growth thin films were examined. 1% boron-doping has no effect on optical properties of TiO₂ thin film; however, optical properties vary with > 1%. From X-ray diffraction spectra, it is seen that TiO₂ thin films together with doping of boron were formed along with TiB₂ hexagonal structure having (111) orientation, B₂O₃ cubic structure having (310) orientation, TiB_0·024O ₂ tetragonal structure having rutile phase (110) orientation and polycrystalline structures. From SEM images, it is seen that particles together with doping of boron have homogeneously distributed and held onto surface.     

Annealing studies on the structural and optical properties of electrodeposited CdO thin films

Cadmium oxide (CdO) thin films were electrodeposited on indium doped tin oxide glass substrates from aqueous solution and subsequently annealed at higher temperatures up to 600 °C in air, oxygen and inert gas ambients, respectively. The effect of annealing on the morphology, crystalline quality and optical properties of CdO films was investigated. The CdO films were polycrystalline in nature and the grain size strongly depended on the annealing temperature as well as annealing ambient. CdO films were highly transparent in the visible region of the spectrum. The transmittance of the films decreased with increasing annealing temperatures in all the three ambients. Optical bandgap of the nanocrystalline CdO films varied in the range of 2.20–2.54 eV.     

Effect of Mn doping on the structural,morphological, optical and magnetic properties of indium tin oxide films

We report on the preparation and characterization of high purity manganese (3–9 wt.%) doped indium tin oxide (ITO, In:Sn = 90:10) films deposited by sol–gel mediated dip coating. X-ray diffraction and selected area electron diffraction showed high phase purity cubic In₂O₃ and indicated a contraction of the lattice with Mn doping. High-resolution transmission electron microscopy depicted a uniform distribution of ∼20 nm sized independent particles and particle induced x-ray emission studies confirmed the actual Mn ion concentration. UV-Vis diffuse reflectance measurements showed band gap energy of 3.75 eV and a high degree of optical transparency (90%) in the 100–500 nm thick ITO films. X-ray photoelectron spectroscopy core level binding energies for In 3d_5/2 (443.6 eV), Sn 3d_5/2 (485.6 eV) and Mn 2p_3/2 (640.2 eV) indicated the In³⁺, Sn⁴⁺ and Mn²⁺ oxidation states. Magnetic hysteresis loops recorded at 300 K yield a coercivity H_c ∼ 80 Oe and saturation magnetization M_s ∼ 0.39 μ_B/Mn²⁺ ion. High-temperature magnetometry showed a Curie temperature T _c > 600 K for the 3.2% Mn doped ITO film.     

Growth and optical properties of nanostructured ZnS:Mn films

Nanostructured ZnS:Mn films have been grown and their structure, optical properties, and photoluminescence have been studied. The nanostructured ZnS:Mn films have been grown on silicon and glass substrates via hydrochemical deposition from solution. The crystal structure and microstructure of the films have been studied by X-ray diffraction and atomic force microscopy. The band gap of the nanostructured ZnS:Mn films has been determined. The intensity of their photoluminescence bands has been shown to increase with decreasing nanoparticle size.     

Synthesis,characterization and photoresponse study of undoped and transition metal (Co,Ni, Mn) doped ZnO thin films

The synthesis, characterization and photoresponse studies of undoped and transition metal doped zinc oxide thin films are carried out in this work, in prospect of visible light photo detection and sensor applications. The undoped and transition metal ions such as, Co, Ni and Mn doped ZnO films in this study were synthesized by chemical solution deposition, involving spin-coating. We have characterized the deposited films using X-ray diffraction, scanning electron microscopy, photoluminescence and UV–vis spectroscopy studies. The devices of the films for photoresponse study were fabricated by top Ag contacts on the film surface in metal–semiconductor–metal configuration. The current–voltage characteristics and switching measurements of these devices were studied under the illumination of an incandescent lamp. We found a high ON/OFF ratio of 8 and highest photocurrent density of 0.7 mA/cm² for Ni doped ZnO film.     

pH-induced modification on the structural, optical and morphological properties of Zn0.94Ni0.04Mn0.02O nanopowders

Zn_0.94Mn_0.02Ni_0.04O nanopowders were synthesized with different pH values from 4 to 10 by sol–gel method. The X-ray diffraction pattern confirmed that all the samples had hexagonal wurtzite structure. In the acid environment (pH = 4), the reaction rate was very slow and provided the poor crystal quality (D = 16.2 nm). Average crystal size was maximum (24.2 nm) with elliptical shape at pH = 8 which is attributed to the availability of much (OH)^? ions in the base solution. The observed constant c/a ratio revealed that there was no change in hexagonal wurtzite structure by pH. The energy dispersive X-ray spectra confirmed the presence of Ni and Mn in Zn–O lattice. The optical absorption spectra showed that the absorption was increased up to pH = 8 due to de-generated defect states and vacancies. The observed high intensity defect related green band around 488 nm at pH = 8 was due to the improved crystal size in addition to the presence of defects related phases. A weak absorption band around 391 nm observed only at pH = 10 was originated from the intrinsic defects and the interstitial position of Zn²⁺ ion. The higher transmittance (≈90 %) noticed at pH = 10 showed the way to the industrial applications especially as transparent electrode. The continuous blue shift in band gap from 3.61 (pH = 4) to 3.68 eV (pH = 10) is explained by Burstein–Moss effect. Presence of chemical bonding was confirmed by Fourier transform infrared spectra.     

Variation of the key structural,morphological, and optical properties of nanostructured copper(II) oxide (CuO) thin films using surfactant CAPB as a capping agent

Journal of Materials Science: Materials in Electronics - In this study, copper(II) oxide thin-film samples were fabricated by the SILAR technique in the absence and presence of surfactant as a...     

Influence of Mn dopant concentration on film thickness,structural, morphological,compositional and optical properties of zinc oxide thin films

Thin films of zinc oxide (ZnO) and manganese doped zinc oxide (ZnO:Mn) have been prepared on glass substrates by the method of successive ionic layer adsorption reaction (SILAR) technique. X-ray diffraction pattern revealed that the prepared films found to exhibit hexagonal structure with preferential orientation along (101) plane. Scanning electron microscopic analysis showed the appearance of needle shaped flower like grains for ZnO and ZnO:Mn. The value of band gap is found to be in the range between 3.01 and 3.26 eV. Photoluminescence spectroscopic analysis showed that increase in value of peak intensity is observed for ZnO:Mn than ZnO.     

(Cd,Mn) Se semimagnetic semiconductor thin films: growth from solution,structural analysis and optical properties

The preparation details and a few aspects pertaining to the crystallographic and spectral characteristics of the Cd_1−xMn_xSe (0≤x≤0.5) semimagnetic semiconductor thin films are presented in this letter. A series of samples were obtained from an alkaline medium (pH≅10±0.2) composed of Cd²⁺, Mn²⁺ and Se²⁻ ions and were co-deposited from their salt solutions to produce thin solid films. The technique offers a free access for growth of these films first by an ion-by-ion condensation and later by adsorption of colloidal particles and is simple, non-expensive and permits for large area depositions. The deposition conditions and process parameters were so manipulated that good quality deposits were obtained. Few of the key parameters are the following: deposition temperature (50 °C), deposition time (120 min), pH (10±0.2) and speed of mechanical churning (70±2 rpm). The CdMnSe deposits were crystalline with preferred orientation along (100) direction and showed homogeneous phase formation up to a value of x equal to 0.1. Beyond this value, both CdSe and MnSe tend to separate out and formed an admixture. The lattice parameters and the intensities of reflections changed continuously with Mn content in CdSe. The optical spectra revealed high absorption coefficient with a band to band direct type of transitions. The estimated energy gap showed decrease, typically from 1.8 to 1.34 eV, on addition of Mn in CdSe and follows non-linear variation. Scanning electron microscopy also suggests the crystalline nature of the deposits.     

Correlation between structural,morphological, and optical properties of spin-coated Poly (2,5-di(hexyloxy) cyanoterephthalylidene) (CN-PPV) thin films

Journal of Materials Science: Materials in Electronics - Conjugated polymers (CPs) play a major role in optical applications due to their unique properties. In this current work, fluorine-doped tin...     

Size dependent structural, optical and morphological properties of ZnS:Cu thin films

ZnS:Cu thin films have been deposited on glass substrate by a simple neutral pH solution synthesis route and chemical bath deposition technique. The copper concentration was varied between 0 and 0.1 M%. The X-ray diffraction and scanning electron microscope studies show the average size of the nanoparticles are below 4 nm (Bohr diameter). The effect of film thickness on the optical and structural properties has been studied. The optical absorption studies show the band gap energy of ZnS:Cu films decreases from 3.68 to 3.43 eV as thickness varied from 318.3 to 334.1 nm. The structural estimation shows the variation in particle size from 2.67 to 3.14 nm with thickness. The insignificant change in band gap may be due to the increase in particle size and quantum size effect.     

A study of structural, optical and magnetic properties of Cr, Ce co-doping in ZnO diluted magnetic semiconductors

We present the structural, optical and magnetic properties of pure ZnO, Zn_0.97Cr_0.03O and Zn_0.96Cr_0.03Ce_0.01O samples, the samples were synthesized by sol–gel method. The microstructures, optical and magnetic properties of samples were investigated by X-ray diffraction (XRD), transmission electron microscope , X-ray photoelectron spectroscopy (XPS), photoluminescence spectroscopy (PL), Raman spectroscopy and vibrating sample magnetometer. XRD and XPS data confirmed the formation of a single phase wurtzite type ZnO structure for all the samples. PL measurements revealed that all the three samples had an UV emission and a defect emission, and the Ce ions doping induced a red shift in the UV emission and an increase in the defect emission. Zn_0.97Cr_0.03O and Zn_0.96Cr_0.03Ce_0.01O samples showed the obvious hysteresis loops at room temperature and the saturation magnetization (Ms) increases with incorporating of Ce.     

Influence of Sr and Mn co-doping on the structural,optical, dielectric,multiferroic properties and band gap tuning in bismuth ferrite ceramics

Journal of Materials Science: Materials in Electronics - Solid state reaction was employed to synthesize the Bi1?xSrxFe1?xMnxO3 (x?=?0.05, 0.10, 0.20, 0.25) ceramic...     

Effect of sol concentration on the structural, morphological, optical and photoluminescence properties of zirconia thin films

ZrO₂ thin films were deposited on quartz substrates from 10 wt.%, 20 wt.% and 40 wt.% solutions of Zirconium-n-butoxide in isopropanol by sol-gel dip-coating technique. Higher concentrated sols of 20 wt.% and 40 wt.% exhibited faster gelation, where as 10 wt.% sol remained stable for two months and films synthesized from this sol remained transparent and continuous even for 12 coatings. Ellipsometric study revealed that refractive index of the films increased with increase in sol concentration which is ascribed to the decrease in porosity. X-ray diffraction study showed that a tailoring of grain size from 7.9 to 39.2 nm is possible with increase in sol concentration. Atomic force microscopy studies showed a change in growth mode from vertical to lateral mode with increase in sol concentration. The film surface revealed positive skewness and high kurtosis values which make them favorable for tribological applications. The average optical transmittance in the visible region is highest (greater than 90%) for the film deposited from 10 wt.% sol. The optical band gap decreased from 5.74 to 5.62 eV with increase in the sol concentration. Photoluminescence (PL) spectra of the films exhibit an increase in the emission intensity with increase in sol concentration which substantiates better crystalline quality of the film deposited from 40 wt.% sol and increase in oxygen vacancies. The “Red shift” of the PL spectra with increase in sol concentration originates from the increase in the grain size with sol concentration which makes it suitable for generation of solid state lighting in light emitting diode.     

Effect of transition metal elements on the structural and optical properties of ZnO nanoparticles

Undoped and transition metal (TM)-doped ZnO nanoparticles (Zn_0.98X_0.02O-NPs, X = Mn, Cr, Co and Fe) were synthesized from a metal nitrate precursor and gelatin by a sol–gel method. The compounds were synthesized at calcination temperatures of 550^°C for 6 h. The synthesized undoped/doped ZnO-NPs were characterized by X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). XRD results indicated that the sample products were crystalline with a hexagonal wurtzite phase. SEM images showed the ZnO-NPs nearly spherical shapes and a non-uniform shape for doped ZnO-NPs. The crystalline development in the ZnO-NPs was investigated by X-ray peak broadening. The size–strain plot (SSP) method was used to study the individual contributions of crystallite sizes and lattice strain of the undoped and doped ZnO-NPs. The obtained results showed that strain of the NPs plays an important role in peak broadening; moreover, the mean crystalline size of the undoped and doped ZnO-NPs estimated from the SEM and the SSP method was highly inter-correlated. Finally, optical properties of the samples were studied by a UV–Vis spectrometer.     

On the structural, morphological, optical and electrical properties of sol-gel deposited ZnO:In films

Indium-doped zinc oxide thin films deposition was performed by the sol-gel technique using homogeneous and stable solutions of zinc acetate 2-hydrate and indium chloride in ethanol. Films were spin coated onto glass substrates. After drying and after a heat treatment at 450 °C, highly transparent (80%-90%) films were obtained. The effect on the structural, morphological, optical and electrical thin films properties of the dopant concentration was investigated. The temperature dependencies of the electrical conductivity under vacuum and in open atmosphere were analysed and discussed.     

Optoelectronic,magnetic and antibacterial properties of CdO thin films doubly doped with Mn (cationic) and F (anionic) ions

This paper outlines the effect of (Mn?+?F) double doping on the structural, morphological, optoelectronic, magnetic and antibacterial properties of CdO thin films. Undoped CdO, Mn-doped CdO and (Mn?+?F) doubly doped CdO films exhibit face-centered cubic structure with a strong (1 1 1) preferential growth. Crystallite size value of the undoped film estimated using the Scherrer formula decreases with Mn doping and with double doping it increases. Cauliflower shaped nanostructures are evinced from the SEM images. Increased optical transparency is observed for the doubly doped films. The optical band gap value of the Mn-doped CdO film is found to be red shifted and for the (Mn?+?F) doubly doped films it is blue shifted which may be attributed to the Moss-Burstein effect. Ferromagnetic ordering is observed for the doped films. The doped films show increased antibacterial efficiency against K. pneumonia a gram ?ve bacteria. The obtained results infer that the CdO films doubly doped with Mn (cationic) and F (anionic) ions exhibited better optical, electrical, magnetic and antibacterial properties.