Effect of lattice mismatch on the epitaxy of sol-gel LiNbO3 thin films

1997 ◽  
Vol 12 (5) ◽  
pp. 1391-1400 ◽  
Author(s):  
T. A. Derouin ◽  
C. D. E. Lakeman ◽  
X. H. Wu ◽  
J. S. Speck ◽  
F. F. Lange
Keyword(s):  
Thin Films ◽  
Buffer Layer ◽  
Lattice Mismatch ◽  
Sol Gel ◽  
Mismatch Strain ◽  
Transmission Electron ◽  
Solution Precursor ◽  
Growth Method ◽  
Film Substrate ◽  
Interfacial Plane

A solution precursor method based on metal alkoxides was used to produce epitaxial LiNbO3 thin films, ≈200 nm thick, on (0001) sapphire substrates. Transmission electron. microscopy revealed that the major cause of surface roughness in these films was grain boundary grooves between mosaic grains with misorientations ≤5°. It is postulated that these low angle boundaries directly result in surface grooving and roughness. The epitaxial films also contained two distinguishable variants in the film/substrate interfacial plane, namely, an aligned variant, and a 60° rotated variant, . A seeded grain growth method was used to minimize the presence of the 60° rotated variant. An epitaxial buffer layer of Fe2O3 was used to lower the mismatch strain, eliminate the 60° rotated variant, and reduce the mosaic nature of the LiNbO3 film. X-ray rocking curve full-width-at-half-maximum (FWHM) values measured on the film peak indicate that the mosaic character can be reduced from 1.5° to 0.76° by using a buffer layer.

Microstructure of SrTiO3 Thin Films as Single Layer and Incorporated in Yba2Cu3O7-x/SrTiO3 Multilayers

1995 ◽  
Vol 401 ◽  
Author(s):  
L. Ryen ◽  
E. Olssoni ◽  
L. D. Madsen ◽  
C. N. L. Johnson ◽  
X. Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Lattice Mismatch ◽  
Single Layer ◽  
Transmission Electron ◽  
Tilt Boundaries ◽  
Interfacial Dislocations ◽  
The Individual ◽  
Film Substrate

AbstractEpitaxial single layer (001) SrTiO3 films and an epitaxial Yba2Cu3O7-x/SrTiO3 multilayer were dc and rf sputtered on (110)rhombohedral LaAIO3 substrates. The microstructure of the films was characterised using transmission electron microscopy. The single layer SrTiO3 films exhibited different columnar morphologies. The column boundaries were due to the lattice mismatch between film and substrate. The boundaries were associated with interfacial dislocations at the film/substrate interface, where the dislocations relaxed the strain in the a, b plane. The columns consisted of individual subgrains. These subgrains were misoriented with respect to each other, with different in-plane orientations and different tilts of the (001) planes. The subgrain boundaries were antiphase or tilt boundaries.The individual layers of the Yba2Cu3O7-x/SrTiO3 multilayer were relatively uniform. A distortion of the SrTiO3 unit cell of 0.9% in the ‘001’ direction and a Sr/Ti ratio of 0.62±0.04 was observed, both in correspondence with the single layer SrTiO3 films. Areas with different tilt of the (001)-planes were also present, within each individual SrTiO3 layer.

Microstructure and Current Transport Properties of YBa2Cu3O7-x/(Ba0.05, Sr0.95)TiO3 Multiple-Layer Thin Films

2003 ◽  
Vol 795 ◽  
Author(s):  
Y. Luo ◽  
R. A. Hughes ◽  
J. S. Preston ◽  
G. A. Botton
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Electrical Properties ◽  
Lattice Mismatch ◽  
Single Layer ◽  
Nanocomposite Films ◽  
Mismatch Strain ◽  
Multiple Layer ◽  
Transmission Electron

ABSTRACTYBa2Cu3O7-x (YBCO) films grown by pulsed laser deposition (PLD) on (100) LaAlO3 (LAO) substrates show a strong thickness dependence on the electrical properties. For example, for films in excess of 0.3 μm, the critical current density decreases with increasing thickness. In contrast, nano-composite films consisting of a series of multiple layers of YBa2Cu3O7-x and (Ba0.05, Sr0.95)TiO3 (BSTO) thin films having a total thickness of 5 μm show improved electrical properties. In order to understand this phenomenon, a detailed microstructural characterization has been undertaken. Transmission electron microscopy (TEM) observations show that cracks, stacking faults, c-║ crystals and secondary phase precipitates are present on the single-layer films, while a high-quality microstructure is observed for the nanocomposite multiple-layer films although defects at YBCO/BSTO interface are still present. In addition, nanocomposite films have a reduced surface roughness. In this complex microstructure, the YBCO/BSTO interfaces and the lattice mismatch strain play a crucial role in controlling the nature of the defects and stability of phases. In order to understand the role of the BSTO layer has on the microstructure, the interfacial mismatch strain and defects are analyzed by high-resolution transmission electron microscopy (HRTEM) in combination with the Moiré fringe technique.

Transmission Electron Microscopy studies of the vacancy ordering in YSI2-X thin films

1991 ◽  
Vol 49 ◽  
pp. 562-563
Author(s):  
F.-R. Chen ◽  
T. L. Lee ◽  
L. J. Chen
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Thin Films ◽  
Diffraction Pattern ◽  
Annealing Temperature ◽  
Lattice Mismatch ◽  
Si Substrate ◽  
Metal Thin Films ◽  
Transmission Electron ◽  
Vacancy Ordering

YSi2-x thin films were grown by depositing the yttrium metal thin films on (111)Si substrate followed by a rapid thermal annealing (RTA) at 450 to 1100°C. The x value of the YSi2-x films ranges from 0 to 0.3. The (0001) plane of the YSi2-x films have an ideal zero lattice mismatch relative to (111)Si surface lattice. The YSi2 has the hexagonal AlB2 crystal structure. The orientation relationship with Si was determined from the diffraction pattern shown in figure 1(a) to be and . The diffraction pattern in figure 1(a) was taken from a specimen annealed at 500°C for 15 second. As the annealing temperature was increased to 600°C, superlattice diffraction spots appear at position as seen in figure 1(b) which may be due to vacancy ordering in the YSi2-x films. The ordered vacancies in YSi2-x form a mesh in Si plane suggested by a LEED experiment.

In-Situ Study of NiO Growth on Textured Nickel Tape Using Environmental Scanning Electron Microscope (ESEM) and Hot Stage

2001 ◽  
Vol 7 (S2) ◽  
pp. 1276-1277
Author(s):  
Y. Akin ◽  
R.E. Goddard ◽  
W. Sigmund ◽  
Y.S. Hascicek
Keyword(s):  
Buffer Layer ◽  
Lattice Mismatch ◽  
Sol Gel ◽  
Surface Oxidation ◽  
Dip Coating ◽  
Buffer Layers ◽  
Superconducting Film ◽  
Environmental Scanning ◽  
Cold Rolling And Annealing

Deposition of highly textured ReBa2Cu3O7−δ (RBCO) films on metallic substrates requires a buffer layer to prevent chemical reactions, reduce lattice mismatch between metallic substrate and superconducting film layer, and to prevent diffusion of metal atoms into the superconductor film. Nickel tapes are bi-axially textured by cold rolling and annealing at appropriate temperature (RABiTS) for epitaxial growth of YBa2Cu3O7−δ (YBCO) films. As buffer layers, several oxide thin films and then YBCO were coated on bi-axially textured nickel tapes by dip coating sol-gel process. Biaxially oriented NiO on the cube-textured nickel tape by a process named Surface-Oxidation- Epitaxy (SEO) has been introduced as an alternative buffer layer. in this work we have studied in situ growth of nickel oxide by ESEM and hot stage.Representative cold rolled nickel tape (99.999%) was annealed in an electric furnace under 4% hydrogen-96% argon gas mixture at 1050°C to get bi-axially textured nickel tape.

scholarly journals Multimodal Surface Instabilities in Curved Film–Substrate Structures

2017 ◽  
Vol 84 (8) ◽  
Author(s):  
Ruike Zhao ◽  
Xuanhe Zhao
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Numerical Simulation ◽  
Period Doubling ◽  
Tubular Structures ◽  
Modulus Ratio ◽  
Future Design ◽  
Mismatch Strain ◽  
Curved Structures ◽  
Film Substrate

Structures of thin films bonded on thick substrates are abundant in biological systems and engineering applications. Mismatch strains due to expansion of the films or shrinkage of the substrates can induce various modes of surface instabilities such as wrinkling, creasing, period doubling, folding, ridging, and delamination. In many cases, the film–substrate structures are not flat but curved. While it is known that the surface instabilities can be controlled by film–substrate mechanical properties, adhesion and mismatch strain, effects of the structures’ curvature on multiple modes of instabilities have not been well understood. In this paper, we provide a systematic study on the formation of multimodal surface instabilities on film–substrate tubular structures with different curvatures through combined theoretical analysis and numerical simulation. We first introduce a method to quantitatively categorize various instability patterns by analyzing their wave frequencies using fast Fourier transform (FFT). We show that the curved film–substrate structures delay the critical mismatch strain for wrinkling when the system modulus ratio between the film and substrate is relatively large, compared with flat ones with otherwise the same properties. In addition, concave structures promote creasing and folding, and suppress ridging. On the contrary, convex structures promote ridging and suppress creasing and folding. A set of phase diagrams are calculated to guide future design and analysis of multimodal surface instabilities in curved structures.

Buffer Layer Thickness and the Properties of InN Thin Films on AIN- Seeded (00.1) Sapphire And (111) Silicon

1994 ◽  
Vol 339 ◽  
Author(s):  
T. J. Kistenmacher ◽  
S. A. Ecelberger ◽  
W. A. Bryden
Keyword(s):  
Thin Films ◽  
Buffer Layer ◽  
Layer Thickness ◽  
Electrical Transport ◽  
Lattice Mismatch ◽  
Electrical Mobility ◽  
Seeded Growth ◽  
Electrical Transport Properties ◽  
Buffer Layer Thickness ◽  
Homogeneous Strain

ABSTRACTIntroduction of a buffer layer to facilitate heteroepitaxy in thin films of the Group IIIA nitrides has had a tremendous impact on growth morphology and electrical transport. While AIN- and self-seeded growth of GaN has captured the majority of attention, the use of AIN-buffered substrates for InN thin films has also had considerable success. Herein, the properties of InN thin films grown by reactive magnetron sputtering on AIN-buffered (00.1) sapphire and (111) silicon are presented and, in particular, the evolution of the structural and electrical transport properties as a function of buffer layer sputter time (corresponding to thicknesses from ∼50Å to ∼0.64 μm) described. Pertinent results include: (a) for the InN overlayer, structural coherence and homogeneous strain normal to the (00.1) growth plane are highly dependent on the thickness of the AIN-buffer layer; (b) the homogeneous strain in the AIN-buffer layer is virtually nonexistent from a thickness of 200Å (where a significant X-ray intensity for (00.2)AIN is observed); and (c) the n-type electrical mobility for films on AIN-nucleated (00.1) sapphire is independent of AIN-buffer layer thickness, owing to divergent variations in carrier concentration and film resistivity. These effects are in the main interpreted as arising from a competition between the lattice mismatch of the InN overlayer with the substrate and with the AIN-buffer layer.

scholarly journals Chemical Bath Deposition of Cd1−xZnxS as Buffer Layer in CIGS Solar Cell

2021 ◽  
Author(s):  
Yuming Xue ◽  
Xinyu Wang ◽  
Liming Zhang ◽  
Shipeng Zhang ◽  
Lang Wang ◽  
...  
Keyword(s):  
Thin Films ◽  
Solar Cell ◽  
Buffer Layer ◽  
Chemical Bath Deposition ◽  
Deposition Rate ◽  
Lattice Mismatch ◽  
Solution Concentration ◽  
State Density ◽  
Cubic Phase ◽  
Cigs Solar Cell

Cd1-xZnxS thin films were deposited on glass substrates by chemical bath deposition (CBD). The effect of ZnSO4 solution concentration on the properties of the thin films was analyzed. The concentration of ZnSO4 solution affects the deposition rate of Cd1-xZnxS thin films. When the deposition rate is low, Cd1-xZnxS cubic crystal phase is formed. The surface morphology of hexagonal Cd1-xZnxS thin films is denser than that of cubic phase, the lattice mismatch rate of cubic phase Cd1-xZnxS thin films and CIGS is lower, only 0.56%, the interfacial state density is lower. SCAPS software was used to simulate the performance of the buffer layer, and the conversion efficiency of the cubic phase Cd1-xZnxS buffer layer in CIGS Solar Cell was up to 23.50%. Based on the EDS results, the function relationship between the contents of Zn2+ and Cd2+ in the films and the band gap content was deduced.

DEPOSITION ON VICINAL SUBSTRATES FOR DOMAIN SELECTION IN YBa2Cu3O7 FILMS

2000 ◽  
Vol 14 (25n27) ◽  
pp. 2646-2651
Author(s):  
F. RICCI ◽  
F. CARILLO ◽  
F. LOMBARDI ◽  
F. MILETTO GRANOZIO ◽  
U. SCOTTI DI UCCIO ◽  
...  
Keyword(s):  
Thin Films ◽  
Buffer Layer ◽  
Space Mapping ◽  
X Ray Diffraction ◽  
Vicinal Surfaces ◽  
Reciprocal Space Mapping ◽  
X Ray ◽  
Growth Properties ◽  
Domain Selection ◽  
Film Substrate

(110) and (103) YBa 2 Cu 3 O 7 films have been grown onto exact and vicinal (110) SrTiO 3 substrates, and on vicinal (110) MgO substrates with a SrTiO 3 buffer layer. The samples are carefully characterised by reciprocal space mapping with x-ray diffraction, in order to investigate the features of the typical double domain of (110) and (103) YBa 2 Cu 3 O 7 structure. It is demonstrated that vicinal cut substrates allow to select one film/substrate epitaxial relation. The growth properties of these thin films deposited on vicinal surfaces are discussed.

Influence of Bi3.15Nd0.85Ti3O12 Buffer Layer on Structure and Electrical Properties of Bi0.94Ce0.06Fe0.97Ti0.03O3 Thin Films

2014 ◽  
Vol 703 ◽  
pp. 51-55
Author(s):  
Jia Zeng ◽  
Ming Hua Tang ◽  
Zhen Hua Tang ◽  
Yong Guang Xiao ◽  
Long Peng ◽  
...  
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Buffer Layer ◽  
Current Density ◽  
Coercive Field ◽  
Remnant Polarization ◽  
Sol Gel ◽  
Hysteresis Loops ◽  
Si Substrates ◽  
Sol Gel Process

Bi0.94Ce0.06Fe0.97Ti0.03O3 and Bi0.94Ce0.06Fe0.97Ti0.03O3/Bi3.15Nd0.85Ti3O12 double-layered thin films were fabricated via sol-gel process on Pt/Ti/SiO2/Si substrates. The influence of Bi3.15Nd0.85Ti3O12 buffer layer on microstructure and electrical properties of Bi0.94Ce0.06Fe0.97Ti0.03O3 thin films were investigated in detail. Well-saturated P-E hysteresis loops can be obtained in Bi0.94Ce0.06Fe0.97Ti0.03O3 films with Bi3.15Nd0.85Ti3O12 buffer. The remnant polarization (2Pr) of the double-layered thin films is 112 μC/cm2. The coercive field (2Ec) of double-layered films is 672 kV/cm, which is much lower than that of the Bi0.94Ce0.06Fe0.97Ti0.03O3 thin films. The leakage current density of Bi0.94Ce0.06Fe0.97Ti0.03O3/Bi3.15Nd0.85Ti3O12 double-layered thin films is 4.12×10-5 A/cm2.

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