Synthesis and structural characterization of rutile SnO2 nanocrystals

2003 ◽  
Vol 18 (6) ◽  
pp. 1289-1292 ◽  
Author(s):  
Zhiwen Chen ◽  
J. K. L. Lai ◽  
C. H. Shek ◽  
Haydn Chen
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Pulse Laser Deposition ◽  
Pulse Laser ◽  
Tin Dioxide ◽  
Laser Deposition ◽  
Gas Sensitivity ◽  
Transmission Electron ◽  
Average Grain Size

Nanocrystalline tin dioxide (SnO2) thin films were prepared on glass substrate by pulse laser deposition for the first time. The thin films were characterized for their composition, morphology, and crystalline structure by x-ray diffraction, transmission electron microscopy, and high-resolution transmission electron microscopy. It was found that the thin films consisted only of the tetragonal phase SnO2 with no structural change, and they were well crystallized during deposition. In most cases, SnO2 particles were overlapped, predominantly grown on preferred (101) plane, and connected with two or three neighbors through necks. The average grain size of the as-prepared thin films was about 12 nm. These facts are of great importance for sensor characteristics, since smaller grains and preferred orientation properties provide higher gas sensitivity to the whole thin films. Our findings indicate that the n-type wide-band-gas semiconductor nanocrystalline thin films can be manipulated by using pulse laser deposition techniques, offering new opportunities to control material fabrication.

(111)p microtwinning in SrRuO3 thin films on (001)p LaAlO3

2009 ◽  
Vol 65 (6) ◽  
pp. 694-698 ◽  
Author(s):  
Y. Han ◽  
I. M. Reaney ◽  
D. S. Tinberg ◽  
S. Trolier-McKinstry
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Orientation Relationship ◽  
Room Temperature ◽  
Pulsed Laser ◽  
Zone Axis ◽  
Laser Deposition ◽  
Transmission Electron ◽  
Diffraction Patterns

SrRuO3 (SRO) thin films grown on (001)p (p = pseudocubic) oriented LaAlO3 (LAO) by pulsed laser deposition have been characterized using transmission electron microscopy. Observations along the 〈100〉p directions suggests that although the SRO layer maintains a pseudocube-to-pseudocube orientation relationship with the underlying LAO substrate, it has a ferroelastic domain structure associated with a transformation on cooling to room temperature to an orthorhombic Pbnm phase (a − a − c + Glazer tilt system). In addition, extra diffraction spots located at ±1/6(ooo)p and ±1/3(ooo)p (where `o' indicates an index with an odd number) positions were obtained in 〈110〉p zone-axis diffraction patterns. These were attributed to the existence of high-density twins on {111}p pseudocubic planes within the SrRuO3 films rather than to more conventional mechanisms for the generation of superstructure reflections.

A Simple and Effective Route to Annihilate Defects in Nanocrystalline SnO2 Thin Films Prepared by Pulsed Laser Deposition

2007 ◽  
Vol 1026 ◽  
Author(s):  
Zhiwen Chen ◽  
C. M. L. Wu ◽  
C. H. Shek ◽  
J. K. L. Lai ◽  
Z. Jiao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Pulsed Laser Deposition ◽  
Gas Sensors ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Transmission Electron ◽  
Sno2 Thin Films

AbstractThe microstructural defects of nanocrystalline SnO2 thin films prepared by pulsed laser deposition have been investigated using transmission electron microscopy, high-resolution transmission electron microscopy and Raman spectroscopy. Defects inside nanocrystalline SnO2 thin films could be significantly reduced by annealing the SnO2 thin films at 300 °C for 2 h. High-resolution transmission electron microscopy showed that stacking faults and twins were annihilated upon annealing. In particular, the edges of the SnO2 nanoparticles demonstrated perfect lattices free of defects after annealing. Raman spectra also confirmed that annealing the specimen was almost defect-free. By using thermal annealing, defect-free nanocrystalline SnO2 thin films can be prepared in a simple and practical way, which holds promise for applications as transparent electrodes and solid-state gas sensors.

Transmission Electron Microscopy of Pzt Thin-Films Prepared by A Sol-Gel Technique

1993 ◽  
Vol 310 ◽  
Author(s):  
Supapan Seraphin ◽  
Dan Zhou ◽  
G. Teowee ◽  
J.M. Boulton ◽  
D.R. Uhlmann
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Lead Zirconate Titanate ◽  
Sol Gel ◽  
Chemical Compositions ◽  
Pzt Thin Films ◽  
Transmission Electron ◽  
Average Grain Size ◽  
Gel Technique

AbstractThe microstructure of lead zirconate titanate (PZT) thin films prepared by a sol-gel technique was investigated using transmission electron microscopy (TEM) and transmission electron diffraction. We investigated the microstructure of three sets of thin films with different chemical compositions: PZT 53/47 films with no excess PbO; with excess PbO; and PZT 65/35 with no excess PbO. All samples were fired for 30 minutes at temperatures ranging from 400C to 700C. Incorporation of excess PbO in the 53/47 film fired at 450C resulted in polycrystalline perovskite grains with an average grain size of less than 0.1 μm. Grain boundaries are decorated by 5-10 nm diameter precipitates possibly caused by the segregation of remnant pyrochlore or excess PbO. The films have high values of dielectric constant (up to 2500) when fired at 700C. PZT 65/35 fired at 700C consists of two distinct phases: a fine-grained matrix of pyrochlore, and 10-μm diameter rosettes of perovskite. The correlations between the compositions, the microstructure of the films, and their processing conditions on the one hand, and ferroelectric properties on the other are discussed.

Synthesis and Characterization of Metal-Ceramic Thin Film Nanocomposites With Improved Mechanical Properties

2002 ◽  
Author(s):  
D. Kumar ◽  
N. Sudhir ◽  
S. Yarmolenko ◽  
Q. Wei ◽  
J. Sankar ◽  
...  
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Transmission Electron ◽  
Thin Film Composites ◽  
Film Composites

Thin films composite materials consisting of metallic nanocrystals embedded in an insulator host have been synthesized using alternating-target pulsed laser deposition of Fe/Ni and Al2O3. The evaluation of structural quality of the thin film composites using high resolution transmission electron microscopy and scanning transmission electron microscopy with atomic number contrast has revealed the formation of a biphase system with thermodynamically driven segregation of Ni and alumina during pulsed laser deposition. The best hardness values of the thin film composites, measured using nanoindentation techniques, was found to 20–30% larger than pure alumina films fabricated under identical conditions. The improvement in values of hardness of Al2O3 thin films by embedding metal nanocrystals is related to the evolution of a microstructure which efficiently hinders the manipulation and movement of dislocation and the growth of microcracks, which in turn, is achieved by grain boundary hardening.

Transmission Electron Microscopy Studies of Tin Oxide Thin Films Grown on the Sapphire Substrate

1998 ◽  
Vol 4 (S2) ◽  
pp. 622-623
Author(s):  
L. Fu ◽  
X. Pan
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Sapphire Substrate ◽  
Tin Oxide ◽  
Tin Dioxide ◽  
High Ratio ◽  
Crystal Defects ◽  
Oxide Thin Films ◽  
Transmission Electron

Tin dioxide (SnO2) with rutile type structure exhibits unique electronic and optical properties. In applications of this material as gas sensors, a film-type of SnO2 provides high ratio of surface area to volume and lead to high sensitivity and fast responses. It has been found that substrate material, deposition conditions, and annealing procedure may directly control the microstructure of thin films, hence control gas-sensing properties. In this paper, we present transmission electron microscopy (TEM) studies of the microstructure and crystal defects of tin oxide thin films on sapphire substrate with subsequent annealing at high temperatures.Tin oxide thin films were deposited on the surface of sapphire by e-beam evaporation of high purity SnO2 (99.999%) at 350°C followed by annealing in air at 600°C - 700°C. Microstructures of the films were characterized by X-ray diffraction (XRD) and TEM techniques.

Growth Temperature and Oxygen Ambient Dependency of SrTiO3/Si(100) InterfaceStructures

2001 ◽  
Vol 700 ◽  
Author(s):  
Parhat Ahmet ◽  
Takashi Koida ◽  
Mamoru Yoshimoto ◽  
Hideomi Koinuma ◽  
Toyohiro Chikyow
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Growth Temperature ◽  
Interfacial Layer ◽  
Laser Deposition ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Interface Structures

AbstractA systematical growth temperature and oxygen ambient dependency of SrTiO3/Si interface structures were investigated using a growth temperature gradient pulse laser deposition (PLD) system and cross sectional high resolution transmission electron microscopy (HRTEM). A SiO2 interfacial layer and an amorphized SrTiO3 layer were observed at the interface for the thin films grown on Si (100) at growth temperatures above 600°C. Our results show that at growth temperatures higher than 600°C, the formation of the amorphized SrTiO3 layer is strongly growth temperature and also oxygen partial pressure dependent.

scholarly journals Gas sensitivity properties of TiO2/Ag nanocomposite films prepared by pulse laser deposition

2018 ◽  
Vol 15 (35) ◽  
pp. 48-63
Author(s):  
Nassar A. Al-Isawi
Keyword(s):  
Thin Films ◽  
Pulse Laser Deposition ◽  
Noble Metal ◽  
Pulse Laser ◽  
Laser Energy ◽  
Growth Parameters ◽  
Pure Tio2 ◽  
Laser Deposition ◽  
Nanocomposite Films ◽  
Gas Sensitivity

In this study, a double frequency Q-switching Nd:YAG laser beam (1064 nm and λ= 532 nm, repetition rate 6 Hz and the pulse duration 10ns) have been used, to deposit TiO2 pure and nanocomposites thin films with noble metal (Ag) at various concentration ratios of (0, 10, 20, 30, 40 and 50 wt.%) on glass and p-Si wafer (111) substrates using Pulse Laser Deposition (PLD) technique. Many growth parameters have been considered to specify the optimum condition, namely substrate temperature (300˚C), oxygen pressure (2.8×10-4 mbar), laser energy (700) mJ and the number of laser shots was 400 pulses with thickness of about 170 nm. The surface morphology of the thin films has been studied by using atomic force microscopes (AFM). The Root Mean Square (RMS) value of thin films surface roughness increased with increasing of Ag contents, while the crystallite size was found to decrease with increase in different silver content. The sensitivity toward NO2 and NH3 gas has been measured under different ppm concentrations. TiO2 with noble metal has a sensitivity higher than pure TiO2 where as TiO2 with Ag metal deposited on glass substrate has maximum sensitivity to NO2 gas with a value of ~(50 %) at the nanocomposite 90%TiO2/10%Ag films with best operation temperature at 200 °C. In addition, noble metal like Ag to the titanium dioxide materials makes them sensitive to NO2 gas.

Growth and Characterization of Mg0.15Zn0.85O Thin Films by Pulsed Laser Deposition

2006 ◽  
Vol 957 ◽  
Author(s):  
Wei Wei ◽  
Chunming Jin ◽  
Anand Doraiswamy ◽  
Roger J Narayan ◽  
Jagdish Narayan
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Fused Silica ◽  
Laser Deposition ◽  
Bandgap Energy ◽  
Absorption Data ◽  
Transmission Electron

ABSTRACTMg0.15Zn0.85O thin films were grown on fused silica substrates at different substrate temperatures using pulsed laser deposition. X-ray diffraction and transmission electron microscopy were used to investigate the structure of the films. High resolution transmission electron microscopy showed that the film contained small grains with low angle boundaries. The optical properties of the films were investigated using absorption spectra. The bandgap energy values of the films was determined by fitting the absorption data.

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