Effects of Annealing on Structural and Optical Properties of ZnO Nanowires

2014 ◽  
Vol 1675 ◽  
pp. 21-25
Author(s):  
Anas Mazady ◽  
Abdiel Rivera ◽  
Mehdi Anwar
Keyword(s):  
Annealing Temperature ◽  
Defect Density ◽  
Volume Ratio ◽  
Chemical Vapor ◽  
Optical Quality ◽  
Structural And Optical Properties ◽  
Si Substrates ◽  
Higher Temperature ◽  
First Time

ABSTRACTWe report, for the first time, effects of annealing of ZnO NWs grown on p-Si substrates. ZnO NWs are grown using metalorganic chemical vapor deposition (MOCVD) and thermal annealing was performed in situ under nitrogen ambient at different stages of the growth process. Increasing the annealing temperature of the ZnO seed epi-layer from 635 °C to 800 °C does not affect the morphology of the grown NWs. In contrast, annealing the NWs themselves at 800 °C results in a 48% decrease of the surface area to volume ratio of the grown NWs. The optical quality can be improved by annealing the seed layer at a higher temperature of 800 °C, although annealing the NWs themselves does not affect the defect density.

Formation of Sub-100 NM GE Wires on Si by E-Beam Evaporation/Lithography

1995 ◽  
Vol 380 ◽  
Author(s):  
C. Deng ◽  
J. C. Wu ◽  
C. J. Barbero ◽  
T. W. Sigmon ◽  
M. N. Wybourne
Keyword(s):  
Cross Section ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Si Substrates ◽  
Novel Technique ◽  
Atomic Force ◽  
Transmission Electron ◽  
First Time ◽  
Scanning Electron

ABSTRACTA fabrication process for sub-100 nm Ge wires on Si substrates is reported for the first time. Wires with a cross section of 6 × 57 nm2 are demonstrated. The wire structures are analyzed by atomic force (AFM), scanning electron (SEM), and transmission electron microscopy (TEM). Sample preparation for TEM is performed using a novel technique using both pre and in situ deposition of multiple protection layers using a Focused Ion Beam (FIB) micromachining system.

Variation de la contrainte des verres de silice sous cycle thermique

1992 ◽  
Vol 70 (10-11) ◽  
pp. 830-833
Author(s):  
H. Bouchard ◽  
A. Azelmad ◽  
J. F. Currie ◽  
M. Meunier
Keyword(s):  
Initial Stress ◽  
Vapor Deposition ◽  
Boron Content ◽  
Annealing Temperature ◽  
Chemical Vapor ◽  
Boron Doping ◽  
Pressure Chemical ◽  
Phosphosilicate Glass ◽  
Borophosphosilicate Glass

Using an in situ technique, stress was measured as a function of annealing temperature to investigate the effect of phosphorous and boron doping of silicon dioxide glass films deposited by low-pressure chemical vapor deposition (LPCVD). It was found that the initial stress of phosphosilicate glass is independent of the amount of phosphorus present, while the boron content influences the initial stress in borophosphosilicate glass. The stress increases to a maximum, σm, corresponding to a temperature Tm, above which the onset of viscous flow reduces the stress to zero at a temperature T0. All these parameters are dependant on dopant concentrations. The observed mechanical behavior is discussed in terms of film viscosity.

TEM and SEM Studies of MOCVD-Grown GaP on Si

1985 ◽  
Vol 62 ◽  
Author(s):  
M. M. Ai-Jassim ◽  
J. M. Olson ◽  
K. M. Jones
Keyword(s):  
Defect Density ◽  
Growth Parameters ◽  
Three Dimensional ◽  
Chemical Vapor ◽  
Structural Defects ◽  
Organic Chemical ◽  
Cross Sectional ◽  
Plan View ◽  
Si Substrates ◽  
Antiphase Domains

ABSTRACTGaP and GaP/GaAsP epitaxial layers have been grown on Si substrates by metal-organic chemical vapor deposition (MOCVD). These layers were characterized by SEM and TEM plan-view and cross-sectional examination. At growth temperatures ranging from 600° C to 800° C, the initial stages of growth were dominated by three-dimensional nucleation. TEM studies showed that at high temperatures the nuclei were generally misoriented with respect to each other yielding, upon coalescence, polycrystalline layers. The growth of single-crystal layers was achieved by nucleating a 30–50 nm layer of GaP at 500° C, followed by annealing and continued growth at 750 ° C. The defect density in these structures was investigated as a function of various growth parameters and substrate conditions. A high density of structural defects was generated at the Si/GaP interface. The use of 2° off (100) Si substrates resulted in GaP layers free of antiphase domains. These results and their implications are discussed.

Migration-Enhanced Molecular Beam Epitaxial Growth and Characterization of GaAs on Si Substrates

1988 ◽  
Vol 144 ◽  
Author(s):  
J.H. Kim ◽  
S. Sakai ◽  
J.K. Liu ◽  
G. Raohakrishnan ◽  
S.S. Chang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Molecular Beam ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Cross Sectional ◽  
Light Emitting ◽  
Si Substrates ◽  
Molecular Beam Epitaxial

ABSTRACTWe first report on migration-enhanced molecular beam epitaxial (MEMBE) growth and characterization of the GaAs layers on Si substrates (GaAs/Si). Excellent surface morphology GaAs layers were successfully grown on (100) Sisubstrates misoriented 4 toward [110] direction. The MEMBE growth method isdescribed and material properties are compared with those of normal two-step MBE-grown or in-situ annealed layers. Micrographs of cross-sectional view transmission electron microscopy (TEM) and scanning surface electron microscopy (SEM) of MEMBE-grown GaAs/Si showed dislocation densities of 107 cm-2 over ten times lower than those of two-step MBE-grown or in-situ annealedlayers. AlGaAs/GaAs double heterostructure lasers and light-emitting diodeshave been successfully grown on MEMBE GaAs/Si by both metal organic chemical vapor deposition and liquid phase epitaxy. MOCVD-grown lasers showed peak output power as high as 184 mW/facet, pulsed threshold currents as low as150 mA at 300 K, and differential quantum efficiencies of up to 30 %. The LPE-grown light-emitting diodes showed output powers of 1.5 mW and external quantum efficiencies of 3.3 mW/A per facet.

Residual Stresses in Sputtered ZnO Films on (100) Si Substrates by XRD

2009 ◽  
Vol 1201 ◽  
Author(s):  
Florine Conchon ◽  
Pierre-Olivier Renault ◽  
Philippe Goudeau ◽  
Eric Le Bourhis ◽  
Elin Sondergard ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Annealing Temperature ◽  
Protective Coatings ◽  
Zno Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Si Substrates ◽  
Thermally Activated ◽  
Post Deposition

AbstractResidual stresses in sputtered ZnO films on Si are investigated and discussed. By means of X-ray diffraction, we show that as-deposited ZnO films encapsulated or not by Si3N4 protective coatings are highly compressively stressed. Moreover, a transition of stress is observed as a function of the post-deposition annealing temperature. After a heat treatment at 800°C, ZnO films are tensily stressed while ZnO films encapsulated by Si3N4 are stress-free. With the aid of in-situ X-ray diffraction, we argue that this thermally-activated stress relaxation can be attributed to a variation of the chemical composition of the ZnO films.

Patterned Growth of Long and Clean Boron Nitride Nanotubes on Substrates

2009 ◽  
Vol 1204 ◽  
Author(s):  
Chee Huei Lee ◽  
Ming Xie ◽  
Jiesheng Wang ◽  
Russell E. Cook ◽  
Yoke Khin Yap
Keyword(s):  
Boron Nitride ◽  
Chemical Vapor ◽  
Boron Nitride Nanotubes ◽  
Device Fabrication ◽  
Critical Parameters ◽  
Synthesis Process ◽  
High Quality ◽  
Patterned Growth ◽  
Si Substrates ◽  
First Time

AbstractFor the first time, patterned growth of boron nitride nanotubes (BNNTs) on Si substrates has been achieved by catalytic chemical vapor deposition (CCVD). Following the boron oxide chemical pathway and our growth vapor trapping approach, high quality and quantity BNNTs can be produced. Effective catalysts have been found to facilitate the growth of BNNTs, while some critical parameters of the synthesis have also been identified to control the quality and density. The success of patterned growth of high quality BNNTs not only explains the roles of the effective catalysts during the synthesis process, but could also be of technologically important for future device fabrication.

Defect Reduction of Cvd-Grown Cubic SiC Epitaxial Films on Off-Axis Si(100) Substrates with a Novel Off-Direction.

1990 ◽  
Vol 198 ◽  
Author(s):  
Katsuki Furukawa ◽  
Yoshihisa Fujii ◽  
Akira Suzuki ◽  
Shigeo Nakajima
Keyword(s):  
Defect Density ◽  
Chemical Vapor ◽  
Epitaxial Films ◽  
Defect Reduction ◽  
Fault Density ◽  
Electrolytic Etching ◽  
Order Of Magnitude ◽  
First Time ◽  
Defect Densities ◽  
Sic Films

ABSTRACTMonocrystalline cubic SiC (β -SiC) thin films with lower defect densities have been epitaxially grown by chemical vapor deposition on off-axis Si (100) substrates with off-directions different from the conventional 〈011〉. Stacking faults of β -SiC films are investigated by the electrolytic etching and SEM observation. The effects of off-direction deviated from 〈011〉 are examined for the first time. The off-angle is fixed at 2 degrees. We find a reduction in defect density with increasing deviation angle θ, of off-direction from [011] toward [011[ (θ = 0 - 45°). The defect density becomes one order of magnitude smaller than that of on-axis (100) substrates. A typical value of the stacking fault density is approximately 6 × 106 cm−2 on the substrate with θ = 30° (film thickness: 24μ m).

scholarly journals Smoothening of (001) and (111) Cu films epitaxially grown on Si substrates

2000 ◽  
Vol 648 ◽  
Author(s):  
Rosa Alejandra Lukaszew ◽  
Ctirad Uher ◽  
Roy Clarke
Keyword(s):  
Experimental Data ◽  
Scaling Analysis ◽  
Mbe Growth ◽  
Cu Films ◽  
Si Substrates ◽  
Oriented Films ◽  
Lower Activation ◽  
First Time ◽  
Lower Activation Energy

AbstractWe report an in-situ study of the MBE growth of Cu films on hydrogen-terminated Si (001) and (7×7) reconstructed Si(111) substrates. Using correlated RHEED and STM data, we find a dramatic smoothing of epitaxial Cu(001) surfaces by annealing the as- grown films in the 120-160oC temperature range and somewhat less so for the Cu (111) films. Our measurements reveal a lower activation energy (0.40 ± 0.04 eV) for inter- terrace mass transport in Cu(001) than for Cu(111) (1.10 ± 0.03 eV) the former possibly influenced by the presence of hydrogen. Scaling analysis of the subsequent Cu growth on the annealed smooth surfaces yields a coarsening exponent of 1/4 for the (001) oriented films while this exponent is 1/3 for the (111) films, providing for the first time experimental data for the same system in these two orientations.

In Situ Spectroscopic Ellipsometry Study of the Oxide Etching and Surface Damaging Processes on Silicon Under Hydrogen Plasma

1999 ◽  
Vol 591 ◽  
Author(s):  
I.M. Vargas ◽  
J.Y. Manso ◽  
J.R. Guzmán ◽  
B.R. Weiner ◽  
G. Morell
Keyword(s):  
Spectroscopic Ellipsometry ◽  
Hydrogen Plasma ◽  
Chemical Vapor ◽  
Surface Damage ◽  
Silicon Surfaces ◽  
Native Oxide ◽  
Native Oxide Layer ◽  
Si Substrates ◽  
Oxide Etching

ABSTRACTWe employed in situ ellipsometry in the monitoring of surface damage to monocrystalline silicon (Si) substrates under hydrogen plasma conditions. These measurements were complemented with spectroscopic ellipsometry and Raman spectroscopy, in order to characterize the surface conditions. It was found that heating the Si substrate to 700°C in the presence of molecular hydrogen produces etching of the native oxide layer, which is typically 10 Å thick. When the already hot and bare silicon surface is submitted to hydrogen plasma, it deteriorates very fast, becoming rough and full of voids. Modeling of the spectroscopic ellipsometry data was used to obtain a quantitative physical picture of the surface damage, in terms of roughness layer t ickness and void fraction. The results indicate that by the time a thin film starts to grow on these silicon surfaces, like in the chemical vapor deposition of diamond, the roughness produced by the hydrogen plasma has already determined to a large extent the rough nature of the film to be grown.

Evolution of Defect Photoluminescence in Annealed N-Rich a-SiNx:H Films

2012 ◽  
Vol 531-532 ◽  
pp. 234-237
Author(s):  
Rui Huang ◽  
Jie Song ◽  
Yan Qing Guo ◽  
Chao Song ◽  
Xiang Wang
Keyword(s):  
Luminescence Intensity ◽  
Annealing Temperature ◽  
Chemical Vapor ◽  
Very High Frequency ◽  
Pl Spectra ◽  
Si Substrates ◽  
Annealing Temperatures ◽  
High Frequency Plasma ◽  
Frequency Plasma ◽  
Vapor Deposition Technique

The N-rich a-SiNx:H films were deposited on Si substrates by very high frequency plasma enhanced chemical vapor deposition technique at a low temperature of 250 °C. Strong blue photoluminescence (PL), which originates from nitrogen dangling bond, can be observed in the as-deposited samples. The dependence of defect PL on annealing temperature was systematically investigated. The PL spectra reveal that the PL peak is almost independent of the annealing temperatures while the luminescence intensity rapidly decreases with the annealing temperature increasing from 400°C to 600°C. However, higher annealing temperatures over 700 °C results in an enhancement of luminescence intensity. Based on the relationship between PL spectra and bonding configurations of the samples, the evolution of defect PL with annealing temperatures was briefly discussed.

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