共查询到20条相似文献,搜索用时 24 毫秒
1.
Wang Shu-Fang Yan Guo-Ying Chen Shan-Shan Bai Zi-Long Wang Jiang-Long Yu Wei Fu Guang-Sheng 《中国物理 B》2013,22(3):37302-037302
Three Bi2Sr2Co2Oy thin films with different microstructures have been prepared by chemical solution deposition on LaAlO3(001) through varying the annealing temperature. With the decrease in the annealing temperature, both the size and c-axis alignment degree of grains in the film decrease as well, leading to an increase in the film resistivity. In addition, the decrease in the annealing temperature also results in a slight increase in the seebeck coefficient due to the enhanced energy filtering effect of small-grain film. The nanostructured Bi2Sr2Co2Oy film with the average grain size of about 100 nm shows a power factor comparable to that of the films with larger grains. Since the thermal conductivity of the nanostrcutured films can be depressed due to the enhanced phonon scattering by grain boundary, a higher figure of merit is expected in Bi2Sr2Co2Oy thin film with grains in nanometer size. 相似文献
2.
High temperature thermoelectric properties of highly c-axis oriented Bi<sub>2</sub>Sr<sub>2</sub>Co<sub>2</sub>O<sub>y</sub> thin films fabricated by pulsed laser deposition 下载免费PDF全文
High-temperature thermoelectric transport property measurements have been performed on the highly c-axis oriented Bi2Sr2Co2Oy thin films prepared by pulsed laser deposition on LaAlO3(001).Both the electric resistivity ρ and the seebeck coefficient S of the film exhibit an increasing trend with the temperature from 300 K-1000 K and reach up to 4.8 m·Ω· cm and 202 μV/K at 980 K,resulting in a power factor of 0.85 mW/mK which are comparable to those of the single crystalline samples.A small polaron hopping conduction can be responsible for the conduction mechanism of the film at high temperature.The results demonstrate that the Bi2Sr2Co2Oy thin film has potential application in high temperature thin film thermoelectric devices. 相似文献
3.
Two processes for the fabrication of polycrystalline CoSi2 thin films based on the codeposition of Co and Si by sputtering were studied and compared. The first process involved “annealing after deposition”, where Co and Si are codeposited at ambient temperature and then crystallized by annealing. This process yielded randomly oriented plate-like CoSi2 grains with a grain size that is governed by the nanostructure of the as-deposited film. Polycrystalline CoSi2 thin films were obtained at a process temperature of 170 °C, which was much lower than the annealing temperature of 500 °C needed for Co/Si bilayers. The second process involved “heating during deposition”, where Co and Si are codeposited on heated substrates. This process yielded CoSi2 grains with a columnar structure, and the grain size and degree of (1 1 1) orientation are temperature dependent. The sheet resistance of the resulting films was determined by the preparation temperature regardless of the deposition process used, i.e. “annealing after deposition” or “heating during deposition”. Temperatures of 500 °C and higher were needed to achieve CoSi2 resistivity of 40 μΩ cm or lower for both processes. 相似文献
4.
采用衬底加热溅射铜锌锡硫(CZTS)四元化合物单靶制备CZTS薄膜,并研究原位退火对制备薄膜的影响.结果表明:在溅射结束后快速升温并保持一段时间,所得到的样品相比于未原位退火的CZTS薄膜结晶质量更好,且表面更平整致密;原位退火后的CZTS薄膜太阳电池性能参数也相应地有所提升,其开路电压(V_(OC))为575 mV,短路电流密度(J_(SC))为8.32 mA/cm~2,光电转换效率达到1.82%. 相似文献
5.
6.
Jong-Ho ParkChung-Sik Kim Byung-Chun Choi Jung-Hyun JeongByung Kee Moon Hyo-Jin SeoIll-Won Kim Jin-Soo Kim 《Solid State Communications》2003,127(4):315-318
The dependence of the electrical properties of SrxBiyTa2O9 thin films on the (Bi/Sr ratio 1.6, 2.3, 2.8, 3.4) has been investigated. The SrxBiyTa2O9 ferroelectric thin films were synthesized on Pt/Ti/SiO2/Si substrates using the pulsed laser deposition method. Saturation polarization (Pst) and coercive field (2Ec) depend on the Bi/Sr ratio. Pst increases while Ec decreases with an increase in Bi/Sr ratio. Atomic Force Microscopy images show that the grain size grows with increasing Bi/Sr ratio. It is observed that the impedance behavior in SrxBiyTa2O9 thin film, conforms to the Constant Phase Element (CPE) model. It is believed that the diffuse charges at the grain boundary build up a surface polarization because the impedance behavior close to pure capacitor with grain size increased. 相似文献
7.
SrBi2Nb2O9 (SBN) thin films were prepared on fused quartz substrates at room temperature by pulsed laser deposition. The influence of deposition parameters such as target-to-substrate distance, oxygen pressure and annealing temperature on film crystallization behavior was investigated by X-ray diffraction. Results indicated that the films grown at the optimum processing conditions have polycrystalline structure with a single layered perovskite phase. The optical transmittance of the films prepared at various oxygen pressures was measured in the wavelength range 200–900 nm using UV–vis spectrophotometer. The results showed that there is a red shift in the optical absorption edge with a rise in the oxygen pressure. Refractive index as a function of wavelength and optical band gap of the films were determined from the optical transmittance spectra. The results indicated that the refractive index increases with increasing oxygen pressure at the same incident light wavelength, while the band gap reduces from 4.13 to 3.88 eV. It may be attributed to an increase in packing density and grain size, and decrease in oxygen defects. 相似文献
8.
The structure, magnetic properties and magnetostriction of Fe81Ga19 thin films have been investigated by using X-ray diffraction analysis, scanning electron microscope (SEM), vibrating sample magnetometer and capacitive cantilever method. It was found that the grain size of as-deposited Fe81Ga19 thin films is 50–60 nm and the grain size increases with increase in the annealing temperature. The remanence ratio (Mr/Ms) of the thin films slowly decreases with increase in the annealing temperature. However, the coercivity of the thin films goes the opposite way with increase in the annealing temperature. A preferential orientation of the Fe81Ga19 thin film fabricated under an applied magnetic field exists along 〈1 0 0〉 direction due to the function of magnetic field during sputtering. An in-plane-induced anisotropy of the thin film is well formed by the applied magnetic field during the sputtering and the formation of in-plane-induced anisotropy results in 90° rotations of the magnetic domains during magnetization and in the increase of magnetostriction for the thin film. 相似文献
9.
The coating solutions of nanostructured (Pb1– x Sr x )TiO3 (PST) thin films have been prepared by the sol–gel combined metallo-organic decomposition method. The coating solutions were deposited on Pt/Ti/SiO2/Si substrates using a spin-coating technique with spinning speed of 4300 rpm and annealed at 650°C. The effect of Sr content in reducing the grain size and tetragonal distortion of PST films has been studied. The optimum conditions for crystalline phase formation in the films have been analyzed by thermogravimetric, differential thermal analysis and Fourier transform infrared spectroscopy. The phase and microstructure of the films were studied by X-ray diffraction (XRD) and atomic force microscopy (AFM). The XRD pattern shows that the PST thin films are crystallized into tetragonal structures without any impurity phase and the distortion ratio reduces with increasing Sr concentration. The AFM results indicate an increase in grain size with increasing annealing temperature of the film and reduction in grain size with increasing Sr concentration. 相似文献
10.
Tin oxide (SnO2) thin films (about 200 nm thick) have been deposited by electron beam evaporation followed by annealing in air at 350-550 °C for two hours. Optical, electrical and structural properties were studied as a function of annealing temperature. The as-deposited film is amorphous, while all other annealed films are crystalline (having tetragonal structure). XRD suggest that the films are composed of nanoparticles of 5-10 nm. Raman analysis and optical measurements suggest quantum confinement effects that are enhanced with annealing temperature. For instance, Raman peaks of the as-deposited films are blue-shifted as compared to those for bulk SnO2. Blue shift becomes more pronounced with annealing temperature. Optical band gap energy of amorphous SnO2 film is 3.61 eV, which increases to about 4.22 eV after crystallization. Two orders of magnitude decrease in resistivity is observed after annealing at 350-400 °C due to structural ordering and crystallization. The resistivity, however, increases slightly with annealing temperature above 400 °C, possibly due to improvement in stoichiometry and associated decrease in charge carrier density. 相似文献
11.
N. L. Lazareva V. P. Dresvyanskii A. L. Rakevich V. L. Papernyi O. I. Shipilova S. S. Kolesnikov N. V. Astrakhantsev N. A. Ivanov E. F. Martynovich 《Physics of the Solid State》2016,58(9):1772-1776
The microstructure of lithium fluoride thin films deposited on a glass substrate by thermal vacuum evaporation was investigated. An additional annealing of the films in air at temperatures of 400, 500, and 600°C resulted in an increase in the size of grains forming the film, as well as in the transformation of luminescence spectra of the initial and annealed samples before and after their X-ray irradiation used to generate in the films color centers that played the role of luminescent probes. It was found that an increase in the annealing temperature with an increase in the size of grains leads to a decrease in the intensity of the characteristic photoluminescence bands of color centers in lithium fluoride and to the appearance of new luminescence bands that are not characteristic of this material. Based on the results of the X-ray powder diffraction analysis, it was concluded that the increase in the grain size is caused by the change in the chemical composition of the films primarily due to the interaction of lithium fluoride with the substrate material. 相似文献
12.
用电子束蒸发法制备出四种不同Y2O3含量的Y2O3稳定ZrO2(YSZ)薄膜,用X射线衍射和透射光谱测定薄膜的结构和光学性能.结果表明:随着Y2O3含量的增加,ZrO2薄膜从单斜相向高温相(四方相和立方相)转变,获得了结构稳定的YSZ薄膜;YSZ薄膜的晶粒尺寸都比ZrO2薄膜的大,但随着Y2O3加入量的增加,晶粒尺寸有减小的趋势,薄膜表面也趋向光滑平整.所有YSZ薄膜的透射谱线都与ZrO2薄膜相似,在可见光和红外光区都有较高的透过率.Y2O3的加入还可以改变薄膜的折射率,在一定范围内可得到所需的任意折射率. 相似文献
13.
S. Rasool K. Saritha K.T. Ramakrishna Reddy M.S. Tivanov A.V. Trofimova S.E. Tikoto L. Bychto A. Patryn M. Maliński V.F. Gremenok 《Current Applied Physics》2019,19(2):108-113
The structural, compositional, morphological and optical properties of In2S3 thin films, prepared by thermal evaporation technique and annealed in sulfur ambient at different temperatures have been investigated. The grazing incident X-ray diffraction patterns have indicated polycrystalline form and predominantly cubic structure of annealed In2S3 films. The scanning electron microscopy revealed textured surface with uniformly distributed grains and the grain size increased with increase of annealing temperature. The optical parameters of the films have been determined using conventional transmission and reflection spectra as well as from surface photovoltage measurements. 相似文献
14.
Gaolin Zheng Huaping Song Yan Guo Caihong Jia Chunmei Jiao Shaoyan Yang Qinsheng Zhu Zhanguo Wang 《Applied Surface Science》2010,256(8):2606-8120
Post-growth annealing was carried out on ZnO thin films grown by metal-organic chemical vapor deposition (MOCVD). The grain size of ZnO thin film increases monotonically with annealing temperature. The ZnO thin films were preferential to c-axis oriented after annealing as confirmed by X-ray diffraction (XRD) measurements. Fourier transformation infrared transmission measurements showed that ZnO films grown at low temperature contains CO2 molecules after post-growth annealing. A two-step reaction process has been proposed to explain the formation mechanism of CO2, which indicates the possible chemical reaction processes during the metal-organic chemical vapor deposition of ZnO films. 相似文献
15.
Sava? S?nmezo?lu Güven ?ankaya Necmi Serin 《Applied Physics A: Materials Science & Processing》2012,107(1):233-241
Nanostructured TiO2 thin films were deposited on quartz glass at room temperature by sol–gel dip coating method. The effects of annealing temperature
between 200∘C to 1100∘C were investigated on the structural, morphological, and optical properties of these films. The X-ray diffraction results
showed that nanostructured TiO2 thin film annealed at between 200∘C to 600∘C was amorphous transformed into the anatase phase at 700∘C, and further into rutile phase at 1000∘C. The crystallite size of TiO2 thin films was increased with increasing annealing temperature. From atomic force microscopy images it was confirmed that
the microstructure of annealed thin films changed from column to nubbly. Besides, surface roughness of the thin films increases
from 1.82 to 5.20 nm, and at the same time, average grain size as well grows up from about 39 to 313 nm with increase of the
annealing temperature. The transmittance of the thin films annealed at 1000 and 1100∘C was reduced significantly in the wavelength range of about 300–700 nm due to the change of crystallite phase. Refractive
index and optical high dielectric constant of the n-TiO2 thin films were increased with increasing annealing temperature, and the film thickness and the optical band gap of nanostructured
TiO2 thin films were decreased. 相似文献
16.
As a result of using time-temperature gradient annealing, the structural and optical properties and hence, thermal properties of ZrO2 thin films deposited by electron gun, enhanced considerably compared with rapid thermal annealing. Also, it can be seen time- temperature gradient annealing caused to decrease the total stress and number of thermal barrier along the film. Therefore, according to our experimental results, which is agree with theoretical analysis, the laser induced damage threshold of ZrO2 films can be enhanced significantly compared with rapid annealing procedure. 相似文献
17.
Al2O3/SiO2 films have been prepared by electron-beam evaporation as ultraviolet (UV) antireflection coatings on 4H-SiC substrates and annealed at different temperatures. The films were characterized by reflection spectra, ellipsometer system, atomic force microscopy (AFM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. As the annealing temperature increased, the minimum reflectance of the films moved to the shorter wavelength for the variation of refractive indices and the reduction of film thicknesses. The surface grains appeared to get larger in size and the root mean square (RMS) roughness of the annealed films increased with the annealing temperature but was less than that of the as-deposited. The Al2O3/SiO2 films maintained amorphous in microstructure with the increase of the temperature. Meanwhile, the transition and diffusion in film component were found in XPS measurement. These results provided the important references for Al2O3/SiO2 films annealed at reasonable temperatures and prepared as fine antireflection coatings on 4H-SiC-based UV optoelectronic devices. 相似文献
18.
Bi3TiNbO9:Er3+:Yb3+ (BTNEY) thin films were fabricated on fused silica by pulsed laser deposition. It was demonstrated that different laser fluence and substrate temperature during growth of BTNEY upconversion photoluminescence (UC-PL) samples control the film’s grain size and hence influences the UC-PL properties. The average grain size of BTNEY thin films deposited on fused silica substrates with laser fluence 4, 5, 6, and 7 J/cm2 are 30.8, 35.9, 40.6, and 43.4 nm, respectively. The 525 nm emission intensities increase with the deposition laser fluence and the emission intensities of BTNEY thin film deposited under 700 and 600 °C are almost 24 and 4 times, respectively, as strong as those of samples under 500 °C. The grain size of BTNEY thin film increases with the increasing temperature. UC-PL of BTNEY films is enhanced by increasing grain size of the films. 相似文献
19.
Haripriya Rath S. Anand M. Mohapatra Priyadarshini Dash T. Som U. P. Singh N. C. Mishra 《Indian Journal of Physics》2009,83(4):559-565
Nanostructured TiO2 thin films have been prepared through chemical route using sol-gel and spin coating techniques. The deposited films were
annealed in the temperature range 400–1000°C for 1 h. The structure and microstructure of the annealed films were characterized
by GAXRD, micro-Raman spectroscopy and AFM. The as-deposited TiO2 thin films are found to be amorphous. Micro-Raman and GAXRD results confirm the presence of the anatase phase and absence
of the rutile phase for films annealed up to 700°C. The diffraction pattern of the film annealed at 800 to 1000°C contains
peaks of both anatase and rutile reflections. The intensity of all peaks in micro-Raman and GAXRD patterns increased and their
width (FWHM) decreased with increasing annealing temperature, demonstrating the improvement in the crystallinity of the annealed
films. Phase transformation at higher annealing temperature involves a competition among three events such as: grain growth
of anatase phase, conversion of anatase to rutile and grain growth of rutile phase. AFM image of the asdeposited films and
annealed films indicated exponential grain growth at higher temperature.
相似文献
20.
采用溶胶-凝胶法在石英玻璃衬底上用旋涂法制备了未掺杂、掺杂钇和掺杂镧的TiO2薄膜样品,对样品在700—1100 ℃范围内进行退火处理,并对样品的拉曼光谱进行了分析.分析表明:随着退火温度的升高,未掺杂TiO2薄膜发生了从锐钛矿相经混相最终向金红石相的转换,掺杂钇和掺杂镧对TiO2薄膜的晶相转换起阻碍作用,掺杂镧的阻碍作用更强;稀土掺杂能使TiO2薄膜晶粒细化,并使晶粒内部应力增大从而阻碍晶格振动,掺杂镧比掺杂钇的效果
关键词:
2薄膜')" href="#">TiO2薄膜
稀土掺杂
拉曼光谱
溶胶-凝胶 相似文献