Microstructure of Gold Films Grown by Ion Induced Deposition

1987 ◽  
Vol 101 ◽  
Author(s):  
J.S. Ro ◽  
A.D. Dubner ◽  
C.V. Thompson ◽  
J. Melngailis
Keyword(s):  
Room Temperature ◽  
Growth Conditions ◽  
Micro Structure ◽  
Adsorbed Gas ◽  
Material Deposition ◽  
Transmission Electron ◽  
Deposition Yield ◽  
Gas Molecules ◽  
The Relationship ◽  
Substrate Temperatures

ABSTRACTA beam of ions incident on a substrate can cause adsorbed gas molecules to break up, resulting in material deposition. We have previously demonstrated deposition of gold from a gas of dimethyl gold hexafluoro acetylacetonate (C7H7F6O2Au) using both focused and broad ion beams. Here we investigate growth at various substrate temperatures and examine micro-structure using transmission electron microscopy. Films grown at room temperature were discontinuous even up to the thickness of 250μπι while films grown at higher substrate temperatures were continuous even at lower thicknesses. Deposition carried out on substrates at 100°C and 160°C using 70 kev Ar+ ions resulted in resistivities approaching the bulk value and a deposition yield of 60 to 75 atoms/ion. The relationship between growth conditions, micro-structure and resistivity will be discussed.

(111) Monocrystalline Nickel Films

1972 ◽  
Vol 30 ◽  
pp. 512-513
Author(s):  
T.E. Pratt ◽  
R.W. Vook
Keyword(s):  
Film Thickness ◽  
Deposition Rate ◽  
Room Temperature ◽  
Narrow Range ◽  
High Vacuum ◽  
Residual Pressure ◽  
Temperature Dependent ◽  
Deposition Parameters ◽  
Transmission Electron ◽  
Substrate Temperatures

(111) oriented thin monocrystalline Ni films have been prepared by vacuum evaporation and examined by transmission electron microscopy and electron diffraction. In high vacuum, at room temperature, a layer of NaCl was first evaporated onto a freshly air-cleaved muscovite substrate clamped to a copper block with attached heater and thermocouple. Then, at various substrate temperatures, with other parameters held within a narrow range, Ni was evaporated from a tungsten filament. It had been shown previously that similar procedures would yield monocrystalline films of CU, Ag, and Au.For the films examined with respect to temperature dependent effects, typical deposition parameters were: Ni film thickness, 500-800 A; Ni deposition rate, 10 A/sec.; residual pressure, 10-6 torr; NaCl film thickness, 250 A; and NaCl deposition rate, 10 A/sec. Some additional evaporations involved higher deposition rates and lower film thicknesses.Monocrystalline films were obtained with substrate temperatures above 500° C. Below 450° C, the films were polycrystalline with a strong (111) preferred orientation.

Interfaces in Structural Ceramics

MRS Bulletin ◽  
1990 ◽  
Vol 15 (10) ◽  
pp. 51-59 ◽  
Author(s):  
M. Grant Norton ◽  
C. Barry Carter
Keyword(s):  
Structural Ceramics ◽  
Interface Engineering ◽  
Micro Structure ◽  
Complete Understanding ◽  
Intimate Contact ◽  
Transmission Electron ◽  
Processed Material ◽  
Wide Range ◽  
Alternative Materials ◽  
The Relationship

Structural ceramics are necessarily polycrystalline and their usefulness is largely determined by the interfaces between the grains. The relationship between the structure and chemistry of different interfaces and the micro-structure can be illustrated by reviewing studies of interfaces in a wide range of materials including such classical ceramics as Al2O3, the current “hightech” polyphase ceramics exemplified by ZrO2-toughened Al2O3, and the composite materials of the future. Using transmission electron microscopy is essential for a complete understanding, but limitations to its use must be recognized. Only by understanding the factors that control the behavior of these interfaces will it become possible to further extend the application of interface engineering.Structural ceramics are a group of materials that can be used for applications requiring their strength to persist at high temperatures or in conditions that would be particularly corrosive to alternative materials, which are usually metallic. Strength and strength-related properties such as toughness depend largely on the microstructural features of the processed material.The microstructure is defined by the morphology and size of the grains and the interfaces between these grains. If the grains are in intimate contact, then the interface is a grain boundary of the type familiar from studies of metals.

Optical Detection of Band Gap Variations Due to Ordering in Ga0.47In0.53As on InP

1992 ◽  
Vol 281 ◽  
Author(s):  
D. J. Arent ◽  
K. A. Bertness ◽  
Sarah R. Kurtz ◽  
M. Bode ◽  
J. M. Olson
Keyword(s):  
Band Gap ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
Energy Gap ◽  
Growth Conditions ◽  
Band Gap Energy ◽  
Optical Energy Gap ◽  
Lower Growth ◽  
Transmission Electron ◽  
High Resolution Images

ABSTRACTA reduction in the optical energy gap of more than 65 meV has been observed in In0.53Ga0.47 As grown on (100) InP by atmospheric pressure metalorganic vapor phase epitaxy. The band gap energies were deduced from room temperature photocurrent spectroscopic measurements, accounting for differences in composition and strain. Spontaneous CuPt type ordering of In and Ga atoms on the (111) subplanes of the InGaAs2 was confirmed by transmission electron microscopy. Superlattice signatures in the transmission micrographs were observed only for samples with associated reduced band gap energies, and were confirmed by visible double periodicity in high resolution images. In0.53Ga0.47 As was grown under a variety of conditions, some which promoted ordering. In general, lower growth temperatures and moderate (∼4 μ/hr) growth rates promoted a greater degree of ordering and reduction of the band gap energy. The influence of growth conditions on the ordered structure is considered within the context of current theories.

Interface Formation and the Heteroepitaxy of ZnSe on Si.

1990 ◽  
Vol 198 ◽  
Author(s):  
R. D. Bringans ◽  
D. K. Biegelsen ◽  
F. A. Ponce ◽  
L.-E. Swartz ◽  
J. C. Tramontana
Keyword(s):  
Zinc Selenide ◽  
Room Temperature ◽  
Molecular Beam ◽  
Solid Phase ◽  
Bulk Material ◽  
Znse Crystal ◽  
Si Substrate ◽  
Transmission Electron ◽  
Temperature Deposition ◽  
Substrate Temperatures

ABSTRACTZinc selenide films have been grown heteroepitaxially on Si(100) substrates by molecular beam epitaxy. The growth has been carried out for raised substrate temperatures and also at room temperature followed by solid-phase epitaxial (SPE) regrowth. The ZnSe films have been characterized by a number of surface-sensitive techniques and both the interface and the bulk material have been examined with high resolution transmission electron microscopy (HRTEM). We find that an interlayer, which is most likely SiSex, is present between the ZnSe film and the Si substrate for growths made at 300 °C and causes loss of epitaxy. In the case of room temperature deposition and SPE, it is absent, leading to good epitaxy. In the latter situation, the films are very uniform and there is a 4° rotation of the ZnSe crystal axes relative to those of the Si substrate.

scholarly journals Hydrogen Detection with SAW Polymer/Quantum Dots Sensitive Films

Sensors ◽  
2019 ◽  
Vol 19 (20) ◽  
pp. 4481 ◽  
Author(s):  
Izabela Constantinoiu ◽  
Cristian Viespe
Keyword(s):  
Heat Treatment ◽  
Quantum Dots ◽  
Room Temperature ◽  
Limit Of Detection ◽  
Composite Films ◽  
High Specific Surface Area ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Heat Treated ◽  
Gas Molecules

Regarding the use of hydrogen as a fuel, it is necessary to measure its concentration in air at room temperature. In this paper, sensitive composite films have been developed for surface acoustic wave (SAW) sensors, using quantum dots (QDs) and polymers. Si/SiO2 QDs were used due to having a high specific surface area, which considerably improves the sensitivity of the sensors compared to those that only have a polymer. Si/SiO2 QDs were obtained by laser ablation and analyzed by X-ray diffraction and transmission electron microscopy (TEM). Two types of polymers were used: polydimethylsiloxane (PDMS) and polymethylmethacrylate (PMMA). Polymer and polymer with QDs compositions were deposited on the sensor substrate by drop casting. A heat treatment was performed on the films at 80 °C with a thermal dwell of two hours. The sensors obtained were tested at different hydrogen concentrations at room temperature. A limit of detection (LOD) of 452 ppm was obtained by the sensor with PDMS and Si/SiO2 QDs, which was heat treated. The results demonstrated the potential of using QDs to improve the sensitivity of the SAW sensors and to achieve a heat treatment that increases its adsorption capacity of the gas molecules.

Microstructure and Properties of CoSi2 Thin Films on (100) Silicon by Laser Physical Vapor Deposition

1992 ◽  
Vol 285 ◽  
Author(s):  
P. Tiwari ◽  
R. Chowdhury ◽  
J. Narayan
Keyword(s):  
Thin Films ◽  
Vapor Deposition ◽  
Physical Vapor Deposition ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microstructure And Properties ◽  
Transmission Electron ◽  
Substrate Temperatures ◽  
Deposited Films

ABSTRACTLaser physical vapor deposition (LPVD) has been used to deposit thin CoSi2 films on (001)silicon at different substrate temperatures ranging from room temperature to 600°C. Particulate-free silicide thin films were characterized by X-ray diffraction, Rutherford backscattering, and high resolution transmission electron microscopy. We have found that films deposited at 200°C and below are amorphous; 400°C deposited films are polycrystalline whereas films deposited at 600°C are of epitaxial nature. The Effect of subsequent annealing on resistivity of room-temperature deposited thin films has been investigated. The resistivity value decreases to less than 15 μΩcm after annealing making these films suitable for microelectronics applications. The correlation between microstructure and properties of these films are discussed.

Effects of Microstructure on Photoluminescence of SrS:Eu2+,SM3+ thin Films

1993 ◽  
Vol 301 ◽  
Author(s):  
Susan Z. Hua ◽  
L. Salamanca-Riba ◽  
M. Wuttig ◽  
P. K. Soltani
Keyword(s):  
Thin Films ◽  
Substrate Temperature ◽  
Growth Rates ◽  
Growth Conditions ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Substrate Temperatures ◽  
The Eu

ABSTRACTThe microstructure and its effects on the photoluminescence properties of SrS:Eu2+,Sm3+ thin films grown with different conditions were studied by transmission electron microscopy, x-ray diffraction and photoluminescence techniques. The SrS:Eu2+,Sm3+ thin films were prepared by e-beam evaporation at different substrate temperatures and growth rates. Both of these growth conditions affect the crystallinity of the thin films. The Sm3+ emission is stronger in the films grown at higher growth rates and at an optimum substrate temperature. We believe that the stronger Sm3+ emission is due to the higher population of Sm trivalent charge states in the films. Further increase of the substrate temperature increases the grain size in the films, but has no significant effect on the PL emission properties. In contrast, the Eu2+ emission is less sensitive to growth conditions.

Interactions at Metaijinp Interfaces Formed at 300K and 77K

1996 ◽  
Vol 421 ◽  
Author(s):  
J.W. Palmer ◽  
W.A. Anderson ◽  
D.T. Hoelzer ◽  
H. Hardtdegen
Keyword(s):  
Barrier Height ◽  
Room Temperature ◽  
Field Effect Transistors ◽  
Schottky Diodes ◽  
Electronic Devices ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Substrate Temperatures ◽  
Msm Photodetectors ◽  
State Amorphization

AbstractDepositing Pd or Au on n-InP at cryogenic substrate temperatures has previously been found to significantly increase the barrier height of the resulting Schottky diode. Cross-sectional transmission electron microscopy (XTEM) has been performed on Pd/InP and Au/InP interfaces formed at room temperature (RT) and low temperature (LT) to determine the differences responsible for the change in barrier height. In the Pd case, a solid state amorphization which occurs at the interface upon RT metal deposition is nearly eliminated in as-deposited LT Pd/InP diodes. In the Au case, RT deposition results in the initial monolayers of Au entering the InP lattice, while no such effect was observed in the LT Au/InP diodes. It is clear that the LT deposition dramatically reduces the interaction between the metal and substrate, resulting in a greater barrier height. Enhanced barrier height Schottky diodes are crucial to the development of optical and electronic devices on InP. Preliminary results will be discussed on metalsemiconductor- metal (MSM) photodetectors and metal-semiconductor field-effect-transistors (MESFET's) fabricated using the LT process.

Controllable Dimension of ZnO Nanowalls on GaN/c-Al2O3 Substrate by Vapor Phase Epitaxy Method

2008 ◽  
Vol 8 (9) ◽  
pp. 4783-4786 ◽  
Author(s):  
W. Y. Song ◽  
T. I. Shin ◽  
S. M. Kang ◽  
S.-W. Kim ◽  
J. H. Yang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Deep Level ◽  
Free Exciton ◽  
Growth Conditions ◽  
Hexagonal Structure ◽  
X Ray Diffraction ◽  
Al2o3 Substrate ◽  
X Ray ◽  
Transmission Electron ◽  
Ar Gas

Vertically well-aligned ZnO nanowalls were successfully synthesized at 950–1050 °C. Ar gas was introduced into the furnace at a flow rate of 2000–2500 sccm. An Au thin film with a thickness of 3 nm was used as a catalyst. The ZnO nanowalls were successfully grown on the substrate and most of them had nearly the same thickness and were oriented perpendicular to the substrate. The morphology and chemical composition of the ZnO nanowalls were examined as a function of the growth conditions examined. It was found that the grown ZnO nanowalls have a single-crystalline hexagonal structure and preferred c-axis growth orientation based on the X-ray diffraction and higher-solution transmission electron microscope measurements. The room temperature photoluminescence showed a strong free-exciton emission band with negligible deep level emission, indicating the high optical property of our ZnO nanowall samples.

MOCVD Growth of Epitaxial SrTiO3 Thin Films on YBa2 Cu3O7−x/LaAlO3

1993 ◽  
Vol 335 ◽  
Author(s):  
S. Liang ◽  
C. Chern ◽  
Z. Q. Shi ◽  
Y. Lu ◽  
P. Lu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Ac Susceptibility ◽  
Superconducting Property ◽  
Growth Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mocvd Growth ◽  
Transmission Electron ◽  
Substrate Temperatures

AbstractStrontium titanate (SrTiO3) thin films have been epitaxially grown on YB2Cu3O7−x (YBCO)/LaAlO3 at substrate temperatures of 660 to 700°C. X-ray diffraction (XRD) results indicated that single crystalline SrTiO3 thin films were epitaxially grown on the substrate with <100> orientation perpendicular to the substrates. The compositions of the films with different growth conditions were examined by Rutherford backscattering spectroscopy (RBS) and energy dispersive x-ray spectroscopy (EDX). The ratio of Sr/Ti is in the range of 0.9 to 1.1 for the films with a thickness of 1000–2000Å. The surface morphology of the films and the interfaces of the SrTiO3/YBCO structure were examined by scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). Very smooth surface and sharp interface were observed. The superconducting property of the YBCO layer, as measured by ac susceptibility, did not degrade after growth of SrTiO3 film. The dielectric constant as high as 320 was obtained at 100KHz. The leakage current density is less than 1×10−6A/cm2 at 3V operation.

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