Effects of Deposition Temperature and Thermal Treatment on the Structure of C60 and C70 Films

1994 ◽  
Vol 349 ◽  
Author(s):  
I. Rusakova ◽  
A. Hamed ◽  
P.H. Hor
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
High Resolution ◽  
Deposition Temperature ◽  
Room Temperature ◽  
Strong Dependence ◽  
Polycrystalline Thin Films ◽  
Mean Grain Size ◽  
High Resolution Tem ◽  
Solvent Residues

ABSTRACTC60 and C70 polycrystalline thin films, prepared by sublimation of powders onto carbon holey film substrates held at temperatures Ts of 40 and 200 °C, were investigated at room temperature using conventional and high resolution TEM. A strong dependence of grain size on Ts is observed. We obtain a mean grain size ˜25 nm for both C60 and C70 films when using Ts = 40 °C, but this size is ˜250 nm for C60 and ˜130 nm for C70 when using Ts = 200 °C. In all cases, however, an fc.c. structure with a high density of planar defecTs, twins and stacking faulTs, is observed. When a C60 film grown at Ts = 40 °C was annealed for several hours at only about 250 °C in vacuum, recrystallization took place, with grains as large as 250 nm now being present in the film. A condition to observe this recrystallization seems to be that the powder used to grow the film must be dried for long enough periods of time to minimize the amount of solvent residues.

Formation of Large, Orientation-Controlled, Nearly Single Crystalline Si Thin Films on SiO2 Using Contact Printing of Rolled and Annealed Nickel Tapes

2003 ◽  
Vol 762 ◽  
Author(s):  
Hwang Huh ◽  
Jung H. Shin
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
High Resolution ◽  
Amorphous Silicon ◽  
Tem Analysis ◽  
Contact Printing ◽  
Single Crystalline ◽  
High Resolution Tem ◽  
Lateral Crystallization ◽  
Si Films

AbstractAmorphous silicon (a-Si) films prepared on oxidized silicon wafer were crystallized to a highly textured form using contact printing of rolled and annealed nickel tapes. Crystallization was achieved by first annealing the a-Si film in contact with patterned Ni tape at 600°C for 20 min in a flowing forming gas (90 % N2, 10 % H2) environment, then removing the Ni tape and further annealing the a-Si film in vacuum for2hrsat600°C. An array of crystalline regions with diameters of up to 20 μm could be formed. Electron microscopy indicates that the regions are essentially single-crystalline except for the presence of twins and/or type A-B formations, and that all regions have the same orientation in all 3 directions even when separated by more than hundreds of microns. High resolution TEM analysis shows that formation of such orientation-controlled, nearly single crystalline regions is due to formation of nearly single crystalline NiSi2 under the point of contact, which then acts as the template for silicide-induced lateral crystallization. Furthermore, the orientation relationship between Si grains and Ni tape is observed to be Si (110) || Ni (001)

Atomic structure of [0001]-tilt grain boundaries in ZnO:  A high-resolution TEM study of fiber-textured thin films

2004 ◽  
Vol 70 (12) ◽  
Author(s):  
Fumiyasu Oba ◽  
Hiromichi Ohta ◽  
Yukio Sato ◽  
Hideo Hosono ◽  
Takahisa Yamamoto ◽  
...  
Keyword(s):  
Thin Films ◽  
High Resolution ◽  
Grain Boundaries ◽  
Atomic Structure ◽  
High Resolution Tem

Superplasticity and Microstructure Evolution of Electrodeposited Nanocrystalline Nickel

2007 ◽  
Vol 551-552 ◽  
pp. 539-544 ◽  
Author(s):  
S. Ding ◽  
Kai Feng Zhang ◽  
Guo Feng Wang
Keyword(s):  
Grain Size ◽  
Strain Rate ◽  
Room Temperature ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Intergranular Cracking ◽  
Mean Grain Size ◽  
Electrodeposited Nickel ◽  
Superplastic Properties

Nanocrystalline pure nickel (nc-Ni) was produced by pulse electrodeposition and its superplastic properties at and above room temperature were investigated. The electrodeposited nickel has a narrow grain size distribution with a mean grain size of 70nm. Uniaxial tensile tests at room temperature showed that nc-Ni has a limited plasticity but high tensile strength up to 1GPa at strain rates between 10-5 and 10-2s-1. However, when the temperature increased to 420 and higher, test specimens showed uniform deformation and the elongation value was larger than 200%. A maximum elongation value of 380% was observed at 450°C and a strain rate of 1.67x10-3s-1, SEM and TEM were used to examine the microstructures of the as-deposited and deformed specimens. The results indicated that fracture was caused by intergranular cracking and most cracks were originated from the brittle oxide formed during the tensile test. Grain coarsening was observed in the deformed specimen. The role of temperature and strain on grain growth was evaluated by comparing the microstructure of deformed samples with that of samples statically annealed. Deformation mechanism was discussed based upon the deformed microstructure and strain rate jump tests.

Effect of Temperature on the Optical and Morphological Properties of Zinc Oxide Thin Films Prepared by RF Magnetron Sputtering

2015 ◽  
Vol 1115 ◽  
pp. 422-425
Author(s):  
Souad A.M. Al-Bat’hi ◽  
Maizatulnisa Othman
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Zinc Oxide ◽  
Magnetron Sputtering ◽  
Radio Frequency ◽  
Deposition Temperature ◽  
Rf Magnetron Sputtering ◽  
Morphological Properties ◽  
Zno Thin Films ◽  
Effect Of Temperature

This investigation deals with the effect of temperature on the optical and morphological properties of Zinc Oxide thin films prepared by radio-Frequency (RF) magnetron sputtering technique. In the present work, zinc oxide (ZnO) thin films have been deposited on glass substrates from 50°C to 300°C by radio frequency magnetron sputtering. The effects of deposition temperature on the crystallization behaviour and optical properties of the films have been studied. The thin films were characterized using Ultraviolet Visible Spectroscopy (UV-VIS), Field Emission Scanning Electron Microscopy (FESEM) and X-ray Diffraction Analysis (XRD). From the UV-VIS testing, the average transmission percentage of the films is between 80-95% for all deposition temperatures meanwhile the energy gap of ZnO thin films varies from 3.26 eV to 3.35 eV which is not much different from the theoretical value. Also, the grain size is getting smaller from 3.886nm, 3.216nm, 3.119nm and 3.079nm with respect to the increasing deposition temperature 50°C, 100°C, 200°C and 300°C respectively whereas the average grain size per intercept value is increasing. The patterns of the peak were about the same for all deposition temperature where the thin films have polycrystalline hexagonal wurtzite structure with the orientation perpendicular (002) to the substrate surface (c-axis orientation) at 34.5(2θ).

Highly Conductive and Optically Transparent Polycrystalline Iridium Oxide Thin Films Grown by Reactive Pulsed Laser Deposition

1997 ◽  
Vol 472 ◽  
Author(s):  
M.A. El Khakani ◽  
M. Chaker
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Deposition Temperature ◽  
Room Temperature ◽  
Optical Transmission ◽  
Ambient Pressure ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Structure Morphology ◽  
Quartz Substrates

ABSTRACTReactive pulsed laser deposition has been used to deposit IrO2 thin films on both SiO2 and fused quartz substrates, by ablating a metal iridium target in oxygen atmosphere. At a KrF laser intensity of about 1.7 × 109 W/cm2, IrO2 films were deposited at substrate deposition temperatures ranging from room-temperature to 700 °C under an optimum oxygen ambient pressure of 200 mTorr. The structure, morphology, electrical resistivity and optical transmission of the deposited films were characterized as a function of their deposition temperature (Td). High quality IrO2 films are obtained in the 400–600 °C deposition temperature range. They are polycrystalline with preferred orientations, depending on the substrate, and show a dense granular morphology. At a Td as low as 400 °C, highly conductive IrO2 films with room-temperature resistivities as low as (42±6) μΩ cm are obtained. Over the 300–600 °C Td range, the IrO2 films were found to exhibit a maximum optical transmission at 450 °C (∼ 45 % at 500 nm for 80 nm-thick films).

Chemistry, microstructure, and electrical properties at interfaces between thin films of titanium and alpha (6H) silicon carbide (0001)

1995 ◽  
Vol 10 (3) ◽  
pp. 668-679 ◽  
Author(s):  
L.M. Porter ◽  
R.F. Davis ◽  
J.S. Bow ◽  
M.J. Kim ◽  
R.W. Carpenter ◽  
...  
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Electron Beam Evaporation ◽  
Epitaxial Thin Films ◽  
Interfacial Chemistry ◽  
Barrier Heights ◽  
High Resolution Tem ◽  
Reaction Zones

Epitaxial thin films (4–1000 Å) of Ti contacts have been deposited via UHV electron beam evaporation at room temperature on monocrystalline, n-type, alpha (6H)-SiC(0001). The interfacial chemistry and microstructure, and the electrical properties, were investigated at room temperature and after annealing at 700 °C up to 60 min. High resolution TEM analyses revealed the formation during annealing of reaction zones consisting of Ti5Si3 and TiC. The corresponding electrical properties exhibited considerable stability except after an initial 20 min anneal. Current-voltage (I-V) measurements showed that the Ti contacts were rectifying with low ideality factors (n < 1.09) and typical leakage currents of 5 × 10−7 A/cm2 at −10 V. The Schottky barrier heights calculated from x-ray photoelectron spectroscopy and I-V and V-V measurements were between 0.79 and 0.88 eV for the as-deposited contacts and between 0.86 and 1.04 eV for the annealed contacts.

Deposition of polycrystalline thin films with controlled grain size

2005 ◽  
Vol 38 (3) ◽  
pp. 490-496 ◽  
Author(s):  
M Vopsaroiu ◽  
G Vallejo Fernandez ◽  
M J Thwaites ◽  
J Anguita ◽  
P J Grundy ◽  
...  
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Polycrystalline Thin Films
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