Size Effects in BaTiO3 Thin Films

1995 ◽  
Vol 403 ◽  
Author(s):  
X. M. Lu ◽  
J. S. Zhu ◽  
P. Li ◽  
W. Jiang ◽  
X. Liu ◽  
...  

AbstractThe size effects were studied by the measurement of optical transmittance, Raman spectra and mechanical dissipation in BaTiO3 films. The variation of energy gap, Raman peaks, Curie temperature with film thickness and grain size was observed and the possible origin was analyzed.

Coatings ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 23
Author(s):  
Weiguang Zhang ◽  
Jijun Li ◽  
Yongming Xing ◽  
Xiaomeng Nie ◽  
Fengchao Lang ◽  
...  

SiO2 thin films are widely used in micro-electro-mechanical systems, integrated circuits and optical thin film devices. Tremendous efforts have been devoted to studying the preparation technology and optical properties of SiO2 thin films, but little attention has been paid to their mechanical properties. Herein, the surface morphology of the 500-nm-thick, 1000-nm-thick and 2000-nm-thick SiO2 thin films on the Si substrates was observed by atomic force microscopy. The hardnesses of the three SiO2 thin films with different thicknesses were investigated by nanoindentation technique, and the dependence of the hardness of the SiO2 thin film with its thickness was analyzed. The results showed that the average grain size of SiO2 thin film increased with increasing film thickness. For the three SiO2 thin films with different thicknesses, the same relative penetration depth range of ~0.4–0.5 existed, above which the intrinsic hardness without substrate influence can be determined. The average intrinsic hardness of the SiO2 thin film decreased with the increasing film thickness and average grain size, which showed the similar trend with the Hall-Petch type relationship.


1999 ◽  
Vol 594 ◽  
Author(s):  
R. Spolenak ◽  
C. A. Volkert ◽  
K. Takahashi ◽  
S. Fiorillo ◽  
J. Miner ◽  
...  

AbstractIt is well known that the mechanical properties of thin films depend critically on film thickness However, the contributions from film thickness and grain size are difficult to separate, because they typically scale with each other. In one study by Venkatraman and Bravman, Al films, which were thinned using anodic oxidation to reduce film thickness without changing grain size, showed a clear increase in yield stress with decreasing film thickness.We have performed a similar study on both electroplated and sputtered Cu films by using chemical-mechanical polishing (CMP) to reduce the film thickness without changing the grain size. Stress-temperature curves were measured for both the electroplated and sputtered Cu films with thicknesses between 0.1 and 1.8 microns using a laser scanning wafer curvature technique. The yield stress at room temperature was found to increase with decreasing film thickness for both sets of samples. The sputtered films, however, showed higher yield stresses in comparison to the electroplated films. Most of these differences can be attributed to the different microstructures of the films, which were determined by focused ion beam (FIB) microscopy and x-ray diffraction.


2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Pornsiri Wanarattikan ◽  
Piya Jitthammapirom ◽  
Rachsak Sakdanuphab ◽  
Aparporn Sakulkalavek

In this work, stoichiometric Sb2Te3 thin films with various thicknesses were deposited on a flexible substrate using RF magnetron sputtering. The grain size and thickness effects on the thermoelectric properties, such as the Seebeck coefficient (S), electrical conductivity (σ), power factor (PF), and thermal conductivity (k), were investigated. The results show that the grain size was directly related to film thickness. As the film thickness increased, the grain size also increased. The Seebeck coefficient and electrical conductivity corresponded to the grain size of the films. The mean free path of carriers increases as the grain size increases, resulting in a decrease in the Seebeck coefficient and increase in electrical conductivity. Electrical conductivity strongly affects the temperature dependence of PF which results in the highest value of 7.5 × 10−4 W/m·K2 at 250°C for film thickness thicker than 1 µm. In the thermal conductivity mechanism, film thickness affects the dominance of phonons or carriers. For film thicknesses less than 1 µm, the behaviour of the phonons is dominant, while both are dominant for film thicknesses greater than 1 µm. Control of the grain size and film thickness is thus critical for controlling the performance of Sb2Te3 thin films.


2019 ◽  
Vol 27 (03) ◽  
pp. 1950124 ◽  
Author(s):  
MOHAMMED YARUB HANI ◽  
ADDNAN H. AL-AARAJIY ◽  
AHMED M. ABDUL-LETTIF

Nickel(II) phthalocyanine-tetrasulfonic acid tetrasodium salt (NiTsPc) thin films were deposited on glass substrates at different substrate temperatures ([Formula: see text]) by chemical spray pyrolysis (CSP) technique. The substrate temperature varied from 110∘C to 310∘C in 50∘C steps. The substrate surface temperature is the main parameter that determines the film morphology and properties of the thin films. The structural properties of the deposited NiTsPc thin films were investigated by X-ray diffraction (XRD) and from the obtained results, it was shown that depositing thin films using 210∘C as [Formula: see text] results in higher crystallinity. Atomic force microscope (AFM) was employed to obtain the surface topography and to calculate the roughness and grain size. The smoothest thin film surface was obtained when using at 160∘C, while the highest roughness was obtained at 310∘C. The optical properties were investigated by ultraviolet visible (UV-Vis) spectrophotometer and fluorescence spectrophotometer. From the absorption spectra recorded in the wavelength range 190–1100[Formula: see text]nm, two absorption bands were observed, which are known as Soret and Q-band. By observing the absorption spectrum, it can be concluded that the deposited thin films at 110∘C–310∘C have direct energy gap. From Tauc plot relation, the energy gap ([Formula: see text]) was calculated. The values of the energy gap were between 3.05 and 3.14[Formula: see text]eV. It was observed that different [Formula: see text] highly affects the structural and optical properties of the deposited thin films. The crystallinity, grain size, roughness and the optical properties were strongly affected by the different substrate temperatures.


1996 ◽  
Vol 79 (12) ◽  
pp. 9105-9109 ◽  
Author(s):  
C. T. Tsai ◽  
D. S. Chuu ◽  
G. L. Chen ◽  
S. L. Yang

1996 ◽  
Vol 436 ◽  
Author(s):  
Y. S. Kang ◽  
P. S. Ho ◽  
R. Knipe ◽  
J. Tregilgas

AbstractThe mechanical behavior of the metal film on a polymer substrate becomes an important issue in microelectronics metallization. The metal/polymer structure is also useful to investigate the deformation behavior of very thin free-standing metal film since the flexible polymer serves as a deformable substrate. The tensile force-elongation curves have been measured using a microtensile tester for aluminum thin films, deposited on a PMDA-ODA polyimide film, in the thickness range from 60 rum to 480 nm. The stress-strain curves for aluminum films were constructed by subtracting these curves with polyimide curves measured separately. Tensile strength increases linearly with decreasing film thickness from 196 MPa to 408 MPa within the film thickness range studied. This is in good agreement with the published data for free-standing aluminum films in the same thickness range. The measured Young's modulus is lower than the bulk modulus and exhibits no systematic dependence on the film thickness. The microstructures of aluminum films have been examined using a transmission electron microscope (TEM). These films posses the (111)-textured columnar grain structures. Grain sizes exhibit log-normal distributions and the mean grain size increases monotonically with the film thickness. An attempt is made to evaluate the effect of film thickness and grain size on the strength of aluminum thin film and the result is discussed.


2021 ◽  
Vol 2114 (1) ◽  
pp. 012020
Author(s):  
A.S. Abd - Alsada ◽  
M. F. A. Alias

Abstract In this study, zinc oxide: carbon nanotube (ZnO: CNT) nano composite films with varying CNT concentrations (0,3,5,10, and 15) wt percent were generated utilizing the pulsed laser deposition (PLD) procedure on clean glass substrates at room temperature. The impact of CNT concentration on the structural, morphological, and optical features of ZnO: CNT nano thin films as deposited was examined. X-ray diffraction was used to evaluate the structure of the generated ZnO: CNT thin films, while an atomic force microscope was used to explore the morphological features of the nano films (AFM) and field emission scan electron microscopy (FESEM). The optical properties of prepared thin films were characterized and studied using UV-VIS-NIR spectrophotometer. The structures of prepared ZnO: CNT with different concentration of CNT thin films were polycrystalline. ZnO: CNT nano thin films were synthesized in hexagonal phase and the dominate orientation is (101). The crystallite sizes are 32 and 26 nm for (101) and (100)) planes for ZnO and ZnO: 15% CNT nano films respectively. These crystallite size are decreased with increasing CNT (0, 3,5,10 and 15) wt. %. The lowest grain size can be shown for ZnO, while the largest grain size can be seen in ZnO: CNT nano thin with 15% concentration, whereas FESEM micrographs displayed a typically rough, pronounced microstructure, with surface protrusions. The energy gap (Eg) of ZnO: CNT nano thin film with various concentrations is computed. The result analysis shows that Eg decreased with increasing CNT weight concentration. This type of behaviors make the prepared films are good candidate for broad range of applications such as optoelectronic and display devices.


Author(s):  
Reem Sami Ali

Thin films of bismuth oxide have been prepared utilizing vacuum evaporation. XRD anyalysis reveal that all the films were tetragonal polycrystalline structure with a preferred orientation along (002) plane. SEM images indicate that the grain size fall in the category of nanosize. AFM results assure that the nanonstructure behavior of thin films. Optical studies show that these films have a direct transition with optical energy gap equal to 2.5 eV.


Author(s):  
Islam M El radaf ◽  
Hnan Y Alzahrani

Abstract We deposited CuGaSnS4 thin films on soda-lima glass substrates via a spray pyrolysis process. The X-ray diffraction of CuGaSnS4 films established the formation of an orthorhombic single phase. In addition, the structural parameters of the CuGaSnS4 films were estimated by Debye-Scherer’s formulas, which showed that an enhancement in crystallite size (D) values occurred by increasing the thickness of the investigated films. The EDAX pattern of CuGaSnS4 films confirms a stoichiometric composition. The optical results revealed that the CuGaSnS4 films possessed a direct optical energy gap (Eg). The Eg values were reduced from 1.50 to 1.38 eV with the increase in thickness. Also, there was an observed increase in the linear refractive index and the linear absorption coefficient values occurred due to the increased thickness. Finally, the optoelectrical constants of the sprayed CuGaSnS4 films such as the optical conductivity (σopt) and the optical free carrier concentration to effective mass (N_opt/m^* ) were enlarged with increasing film thickness. The nonlinear optical study showed that the increase in film thickness enhanced the nonlinear optical constants of CuGaSnS4 films. The hot-probe procedure shows that the sprayed CuGaSnS4 films expose p-type conductivity.


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