Texture Coefficient TC Research Articles

Structural and morphological properties of CdSe1-xSx thin films obtained by the method of high-frequency magnetron sputtering

CdSe1-xSx (x= 0.3, 0.4 and 0.6) thin films were deposited on quartz and silicon substrates by the method of high-frequency magnetron sputtering. The chemical composition analysis and crystal structure refinement was examined with using X-ray fluorescence spectroscopy and X-ray diffraction data. CdSe1-xSx thin films crystallizes in hexagonal structure (structure type – ZnO, space group P63mc (No. 186)). The lattice parameters (a, c and V), crystallite size (D), strain (ε), dislocation density (δ) and the texture coefficient TC(hkl) was estimated from X-ray diffraction analysis. Units-cell parameters decrease with increasing S content in CdSe1-xSx thin film.

A study of crystalline – texture and anisotropic properties of hexagonal BaFe12O19 sintered by in-situ magnetic-anisotropy spark plasma sintering (MASPS)

In-situ magnetic-anisotropy spark plasma sintering technique (MASPS) was used to produce an anisotropic pellet of BaFe12O19 at different sintering parameters. The crystalline texture and anisotropic properties were studied and investigated by using XRD, FESEM, EDX, relative magnetic texture, and mechanical anisotropy. Among all sintered samples, S1180 exhibited (00L) preferred orientation with a high degree of texture (Lotgering factor and texture coefficient TC are 0.78 and 7.17 respectively), which has resulted from XRD patterns. FESEM images confirmed that the grains were grown and re-oriented along the magnetic easy axis. From the EDX test, the degrees of crystalline texture were 59.18, 5.26, and −5.54 of S1180, S1050, and S920, respectively. S1180 had the highest mechanical anisotropy, where the hardness on the top surface and the cross-section are 603 and 60.8 HV, respectively. Besides, the highly textured sample (S1180) had the highest relative density (88.76%) and the lowest porosity (11.23%). Moreover, the relative degree of magnetic texture (D) of S1180 was 73.97%.

A film-texture driven piezoelectricity of AlN thin films grown at low temperatures by plasma-enhanced atomic layer deposition

Simultaneously inducing preferred crystalline orientation with a strong piezoelectric response in polycrystalline aluminum nitride (AlN) thin films by atomic layer deposition is a technical challenge due to the upscaling of the integration of piezoelectric functionalities, such as sensing and actuation, in micro-devices without any poling process. Utilizing low-temperature plasma-enhanced atomic layer deposition (PE-ALD), highly c-axis-oriented AlN films have been prepared with precise control over the relative composition, purity levels, and chemical states of constituent elements. Tailoring thermodynamic parameters, such as the growth temperature and purging time after the trimethylaluminum precursor pulsing before the N2:H2:Ar plasma reaction, provide the possibility of modulating the texture coefficient and the relative piezoelectric response. The effective transverse piezoelectric e31,f coefficient of 0.37 C/m2 was achieved on the AlN film grown at 250 °C and 30 s with the highest texture coefficient TC(002) of 2.75 along the c-axis orientation. The process proposed, at a low temperature with the highly conformal growth of aluminum nitride thin films by PE-ALD, opens up pathways to design novel piezoelectric functional materials for micro-electro-mechanic system devices with complementary metal oxide semiconductor process temperature compatibility.

Morphological, cathodoluminescence and thermoluminescence studies of defects in diamond films grown by HF CVD technique

A set of diamond layers was synthesized by Hot Filament Chemical Vapor deposition (HF CVD) from methanol-hydrogen (CH3OH–H2) gas mixture. By changing feed gas composition the obtained diamond films show different morphologies and microcrystal sizes as indicate the Scanning Electron Microscopy (SEM) pictures.The obtained diamond films were analysed by Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), cathodoluminescence (CL) and thermoluminescence (TL) spectroscopy.The diamond's microcrystallities preferred orientation in diamond layers was assessed from X-ray diffraction measurements and described by texture coefficient TC(hkl). The cathodoluminescence study clearly shows that relative intensities of the band at 430 nm and at 605 nm changes as the preferred orientation changes from <400> to <220>. It was also shown that the morphology and the microcrystallities preferred orientation has an essential influence on the thermoluminescence properties of polycrystalline diamond layers.

Determination of cathode current efficiency for electrodeposition of ferromagnetic cobalt nanowire arrays in nanochannels with extremely large aspect ratio

Cathode current efficiency for the electrodeposition of cobalt from an acidic aqueous solution, which took place in anodized aluminum oxide (AAO) nanochannels with an average diameter of ca. 25 nm, was determined by Faraday’s first law of electrolysis. The electrodeposited metallic cobalt crystals were grown as an array of nanowires embedded in the nanochannels. The amount of charge consumed for the electrochemical reduction in the nanochannels was estimated considering the time dependence of the cathode current during the electrodeposition of the cobalt nanowires. Meanwhile, the volume of electrodeposition on the cobalt nanowires was determined from the saturated magnetic moment of the nanowires, which was obtained from the magnetization curves. The cathode current efficiency for the electrodeposition of the cobalt nanowire arrays remained at a high level (over 75%) in the cathode potential ranging from −0.70 V to −0.85 V vs. Ag/AgCl. At the cathode potential of −0.80 V, the cathode current efficiency reached 97%. The texture coefficient TC(0 0 2) of the cobalt nanowire arrays increased as the cathodic overpotential for the electrodeposition of cobalt decreased. Due to the extremely large aspect ratio (more than 1000), the cobalt nanowire arrays were spontaneously magnetized in the direction parallel to the long axis of the nanowires. With increasing TC(0 0 2), the coercivity and squareness of the cobalt nanowire arrays also increased up to ca. 1.6 kOe and 0.8, respectively, at room temperature.

Growth of PVD-AlTiN film on Co-based alloy: Preferred orientation and adaptively formed transition layers

To achieve a better understanding of the interaction between the film and the ductile Co-based binder phase in cemented carbide substrate and the associated interface microstructure evolution, a model alloy of 85.1Co–9.2W–4.7Cr3C2–1.0VC was prepared. Ti0.94Si0.06N/TiAlSiN/Al0.52Ti0.48N coating was deposited on the Co-based alloy by a DC magnetron sputtering technique. High-resolution transmission electron microscopy observation and high-resolution energy dispersion spectrum analysis reveal a complex film-substrate structure. An interface-centered bilateral transition layer, i.e., nanocrystalline AlTiN and hcp-Co, and double sub-transition layers, i.e., bcc-W and disordered arrangement of Co atoms are identified. The formation mechanisms for the sub-transition and transition layer are discussed. Based on the AlTiN transition layer phenomenon, the reason for the substantial texture coefficient TC(111) difference between fcc-AlTiN and fcc-TiSiN (5.9/3.6 vs. 2.9) is discussed. Considering the significance of the observed semi-coherent relationship for the bcc-W/AlTiN interface and the positive adaptability of cobalt, suggestions are proposed for the composition design of cemented carbide substrate and the film deposition rate controlling.

Substrate temperature dependent variation in the properties of cadmium telluride thin films deposited on glass

The present study relates to the variation in properties of cadmium telluride (CdTe) thin films deposited via electron beam and thermal vacuum evaporation methods at two different substrate temperatures. The influence of substrate temperature on structural, morphological, optical and electrical properties of CdTe thin films is investigated. For structural characterization, grazing incidence X-ray diffraction technique is used which revealed that thin films deposited at 200 °C temperature are more crystalline in nature as compare to the room temperature. The parameters such as average crystallite size (D), lattice strain (e), number of crystallites per unit area (N) and texture coefficient TC (hkl) were calculated for both types of synthesized CdTe thin films. Surface morphology of thin films was recorded using scanning electron microscopy and found to be homogeneous in nature. The optical studies carried out using UV–Visible Spectrophotometer and Photoluminescence shown a decrease in band gap values for both electron beam and thermally deposited thin films samples at 200 °C substrate temperature. Electrical measurements recorded using two probes method showed the maximum value of current for CdTe thin films deposited by electron beam evaporation method at 200 °C substrate temperature.

Synthesis and Photo-Response of CuS Thin Films by an In Situ Multi-Deposition Process at Room Temperature: A Facile and Eco-Friendly Approach

Uniform hexagonal covellite CuS thin films were deposited at room temperature by an in situ solution chemical reaction using copper precursor solid films as cationic source and ammonium sulfide ethanol solution as anionic reaction medium. We investigated the influence of both ethanolamine and butanol contents used in copper nitrate/ethylene glycol monomethylether (EGME) cationic solution for the preparation of copper precursor solid films, deposition cycle numbers and annealing treatment of the as-grown thin films by X-ray diffraction (XRD), FESEM, energy dispersive X-ray fluorescence EDX, transmission electron microscopy–Selected area electronic diffraction (TEM–SAED), atomic force microscopy (AFM) and ultraviolet-visible-near-infrared (UV-Vis–NIR) measurements. Photo-response of the CuS thin films was characterized by linear sweep voltammetry. The deposited CuS thin films were used to sensitize TiO 2 anodes for solar cell application. The results showed that the CuS films had two-dimension oriented, half-sheet shaped growing morphology standing disorderly but vertically to substrates, and the calculated texture coefficient TC(102) verified that the half-sheet shaped crystallites had (102) plane orientation. This in situ multi-deposition process had an average deposited rate of 9 nm per cycle, and a self-perfect function to grow smooth, uniform and 2D oriented morphology with increase in the dip-cycle numbers. The photocurrent density was 14.5 Ma/cm2 at 1 V versus Ag / AgCl electrode for the annealed CuS thin films. CuS -sensitized TiO 2 solar cells had a maximum conversion efficiency of 0.224%.

Effect of thickness on structural and optical properties of vacuum‐deposited Sn2Sb2S5 thin films

Sn2Sb2S5 thin films in thickness of 100 to 900 nm were deposited on glass substrates using thermal evaporation method. XRD indicated that all the Sn2Sb2S5 samples are polycrystalline in nature having orthorhombic structure. The various structural parameters such as crystalline size (D), dislocation density (δ), strain (ε) and texture coefficient TC (hkl) were calculated and the surface morphology of the films was also analyzed. The optical constants, i.e., refractive index, absorption coefficient and optical band gap of the deposited films have been determined from the analysis of the transmittance and reflectance spectral data over the wavelength range 300–1800nm. The averages transmittance for all films is over 80% in the near infrared spectral range. Furthermore, the absorption coefficient of Sn2Sb2S5 thin films was evaluated and found to be in the range 104–105cm−1 in the UV. However, the optical band gap was found to decrease from 1.72 to 1.5eV when the thickness of films increases.

The Structural, optical and electrical properties of nanocrystalline ZnO:Al thin films

The Al doped ZnO thin films were deposited by ultrasonic spray technique. The influence of Al doping on structural, optical and electrical properties of the ZnO thin films was studied. A set of Al doped ZnO (0–3.5wt.%) were deposited at 350°C. Nanocrystalline films with a hexagonal wurtzite structure with a strong (002) preferred orientation were observed after Al doping. The maximum value of grain size (33.28nm) is attained with Al doped ZnO at 3wt.%. Texture coefficient TC(hkl) of the four major peaks where evaluated. Optically, in visible region the transmissions spectra T(λ) show that the whole doped films exhibit lower values than the non doped one which has as transmittance more than 80%; whereas in the same region the optical transmissions of the doped films are affected by the doping ration. The band gap (Eg) increased after doping from 3.267 to 3.325eV with increasing concentration of doping from 0 to 2.75wt.%, respectively, according to the Burstein–Moss effect (blue shift of Eg) then beyond 3wt.% in doping the band gap exhibit a slight decreasing due to the coexistence of Roth and Burstein–Moss effect. The electrical resistivity of the films decreased from 20 to 5.26 (Ωcm). The best results are achieved with 2.75wt.% Al doped ZnO film.

Spray pyrolysis deposition of p-CdTe films: Structural, optical and electrical properties

The present communication reports the structural, optical and electrical properties of p-CdTe films deposited by using spray pyrolysis technique on thoroughly cleaned sodalime glass substrates at 350°C in inert N2 atmosphere. The films were characterized by using XRD, Raman spectroscopy, XPS, thickness profiler, SEM, EDAX and UV–Visible spectroscopy and Hall parameters measurement. The structural studies showed the formation of pure cubic CdTe in resultant films with crystallite size=32nm. The texture coefficient TC(hkl) indicated preferential orientation of films along [311] and [511] directions. The SEM image showed almost spherical granules with average size of 0.25μm. From UV–Visible spectral data, the maximum absorbance and direct band gap obtained using Tauc plot are found to be 0.94 and Eg=1.44eV respectively for films having thickness, t=3.2μm. The Hot probe experiment, Hall coefficient RH=1.478×103cm3/C, and resistivity ρ=2.228×101Ωcm confirmed the p-type semiconducting behavior of CdTe films. The mobility of majority charge carriers – holes is found to be μ=6.63×101cm2/Vs. The films processed using present work can be treated as possible p-type candidate for fabrication of hetero-junction solar cell.

Influence of substrate temperature on the structural, optical and electrical properties of CdS thin films deposited by thermal evaporation

CdS thin films were deposited onto glass substrates at three different temperatures (20, 100 and 200°C) by vacuum thermal evaporation at 10−5Torr using pure crystal as evaporated targets. The effects of substrate temperature on structural, electrical and optical properties were studied. Structural analysis using X-ray diffraction (XRD) and scanning electronic microscope (SEM) revealed that the films are polycrystalline in nature with a hexagonal wurtzite structure having (002) plane as the preferred orientation. The crystalline size (D), dislocation density (δ), strain (ε) and texture coefficient TC(hkl) were calculated. All the films have high optical transmittance (>80%) in the visible range. The optical band gap values are found to be in the range of (2.3–2.43eV) and found to decrease with increase in substrate temperature. DC electrical conductivity was carried out at room temperature indicating a very low electrical conductivity.

Investigation of Structural and Optical Properties of GDC Thin Films Deposited by Reactive Magnetron Sputtering

The purpose of this paper was to analyze structural and optical properties of gadolinia-doped ceria (GDC, Ce0.9Gd0.1O1.95) thin films. At first the ceria–gadolinia multilayer sandwich systems (4–12 layers) were deposited using reactive magnetron sputtering in the O2/Ar gas mixtures. The films were formed with ≈ 90% ceria and ≈ 10% gadolinia. The GDC thin films deposited on Si (111) substrate were annealed at 600 ◦C for 1 h in air. The thickness of the formed GDC multilayer systems was about 600 nm. The GDC thin film microstructure was investigated by X-ray diffraction and scanning electron microscopy. The texture coefficient Tc(hkl) of GDC films was evaluated from the X-ray diffraction patterns. The crystallite size of GDC films was estimated from the Scherrer equation. Optical properties of the annealed GDC thin films were examined using a laser ellipsometer. The results show that the number of layers has the influence on GDC thin film formation. As follows from the analysis of structural and optical properties of GDC 12 layer system annealed at 600 ◦C for one hour in air has the highest refractive index n = 2.17.

Influence of film thickness and substrate on the growth of sprayed SnO2:F films

SnO2:F films of thicknesses up to 0.5 mu m were deposited by spray pyrolysis on different substrates-Corning 7059, soda-lime glass, Si(111), polycrystalline silicon and amorphous silicon. The influence of film thickness, as well as the substrate nature and morphology, on the growth of the films was studied using an X-ray diffraction technique. The results on preferred growth were analysed using the texture coefficient TC (hkl). It was observed that as the film grows in thickness, the preferred growth (texture) improves up to a particular thickness, beyond which reorientational effects are observed. As a result, the thicker films have a deteriorated texture. The influence of the substrate in governing the growth of the film is noticed up to a certain thickness, beyond which the growth becomes substrate independent. Among the substrates mentioned above, Corning 7059 seems to have the least influence on the growth of the films. Films deposited on Corning 7059 under optimized conditions possess the strongest preferred growth along (200).