Nitrogen Doping in Low-Temperature Halo-Carbon Homoepitaxial Growth of SiC

2008 ◽  
Vol 600-603 ◽  
pp. 159-162 ◽  
Author(s):  
Krista Chindanon ◽  
Huang De Lin ◽  
Galyna Melnychuk ◽  
Yaroslav Koshka
Keyword(s):  
Growth Rate ◽  
Low Temperature ◽  
Nitrogen Doping ◽  
Critical Role ◽  
Growth Conditions ◽  
Vapor Condensation ◽  
Nitrogen Incorporation ◽  
Wide Range ◽  
Complex Temperature ◽  
Site Competition

In this work, nitrogen doping was investigated during the low-temperature halo-carbon epitaxial growth of 4H-SiC on Si- and C-faces. The dependencies of nitrogen incorporation on nitrogen flow rate, Si/C ratio, growth rate, and temperature were investigated. It was established that the efficiency of nitrogen incorporation for the C-face growth at 1300 °C is higher than that for the Si-face for a wide range of the growth conditions. Seeming deviation of the Si/C ratio dependence from the “site-competition” trend confirmed the critical role of the silicon vapor condensation during the low-temperature epitaxy. Opposite trends for the nitrogen doping dependence on the growth rate were observed on the Si- and C-faces. Finally, a complex temperature dependence of the nitrogen doping in the temperature range from 1300 to 1450 0C was observed.

Microbial community composition is linked to Sphagnum acclimation to warming

2021 ◽  
Author(s):  
Tatjana Živković ◽  
Alyssa A Carell ◽  
Gustaf Granath ◽  
Mats B Nilsson ◽  
Manuel Helbig ◽  
...  
Keyword(s):  
Growth Rate ◽  
Host Plant ◽  
Climate Warming ◽  
Elevated Temperatures ◽  
Critical Role ◽  
Temperature Acclimation ◽  
Microbial Interactions ◽  
Germ Free ◽  
Wide Range ◽  
Thermal Origin

<p>Peatlands store about third of the terrestrial carbon (C) and exert long-term climate cooling. Dominant plant genera in acidic peatlands, <em>Sphagnum</em> mosses, are main contributors to net primary productivity. Through associative relationships with diverse microbial organisms (microbiome), <em>Sphagnum</em> mosses control major biogeochemical processes, namely uptake, storage and potential release of carbon and nitrogen. Climate warming is expected to negatively impact C accumulation in peatlands and alter nutrient cycling, however <em>Sphagnum</em>-dominated peatland resilience to climate warming may depend on <em>Sphagnum</em>-microbiome associations. The ability of the microbiome to rapidly acclimatize to warming may aid <em>Sphagnum</em> exposed to elevated temperatures through host-microbiome acquired thermotolerance. We investigated the role of the microbiome on <em>Sphagnum</em>’s ability to acclimate to elevated temperatures using a microbiome-transfer approach to test: a) whether the thermal origin of the microbiome influences acclimation of <em>Sphagnum</em> growth and b) if microbial benefits to <em>Sphagnum</em> growth depend on donor <em>Sphagnum</em> species.</p><p>            Using a full-factorial design, microbiomes were separated from <em>Sphagnum</em> “donor” species from four different peatlands across a wide range of thermal environments (11.4-27°C). The microbiomes were transferred onto germ-free “recipient” <em>Sphagnum</em> species in the laboratory and exposed to a range of experimental temperatures (8.5 – 26.5°C) for growth analysis over 4 weeks.</p><p>            Normalized growth rates were maximized for plants that received a microbiome from a matched “donor” and with a similar origin temperature (ΔT<sub>treatment-origin</sub>: 0.3±0.9°C [±standard error], p = 0.73). For non-matched “donor-recipient” <em>Sphagnum</em> pairs, ΔT<sub>treatment-origin</sub> was slightly negative with -4.1±2.1°C (p = 0.06). The largest growth rate of the “recipient” was measured when grown with a microbiome from a matching “donor” <em>Sphagnum</em> species and was 252% and 48% larger than the maximum growth rate of the germ-free <em>Sphagnum</em> and the non-matched “donor-recipient” <em>Sphagnum</em> pairs, respectively.</p><p>            Our results suggest that the composition of the <em>Sphagnum</em> microbiome plays a critical role in host plant temperature acclimation. We found that microbially-provided benefits to the host plant were most pronounced when: 1) the thermal origin of the microbiome is similar to experimental temperatures, and 2) when donor and recipient <em>Sphagnum</em> species are the same. Together, these results suggest that <em>Sphagnum</em> temperature acclimation can be modulated, in part, by microbial interactions and may potentially play a role in peatland resilience to climate warming.</p>

Transport and Chemical Mechanisms in GaN Hydride Vapor Phase Epitaxy

2002 ◽  
Vol 743 ◽  
Author(s):  
Sergey Yu. Karpov ◽  
Alexander S. Segal ◽  
Darya V. Zimina ◽  
Sergey A. Smirnov ◽  
Alexander P. Sid'ko ◽  
...  
Keyword(s):  
Growth Rate ◽  
Vapor Phase ◽  
Growth Conditions ◽  
Vapor Phase Epitaxy ◽  
Hydride Vapor Phase Epitaxy ◽  
Surface Kinetics ◽  
Chemical Mechanisms ◽  
Horizontal Reactor ◽  
Wide Range ◽  
Transport Effects

ABSTRACTOn the basis of both experimental and theoretical studies, a simple quasi-thermodynamic model of surface kinetics is suggested for Hydride Vapor Phase Epitaxy (HVPE) of GaN, working in a wide range of growth conditions. Coupled with detailed 3D modeling of species transport in a horizontal reactor, the model provides quantitative predictions for the GaN growth rate as a function of process parameters. Significance of transport effects on growth rate uniformity is demonstrated.

Role of Cl/Si Ratio in the Low-Temperature Chloro-Carbon Epitaxial Growth of SiC

2013 ◽  
Vol 740-742 ◽  
pp. 205-208
Author(s):  
Galyna Melnychuk ◽  
Siva Prasad Kotamraju ◽  
Yaroslav Koshka
Keyword(s):  
Growth Rate ◽  
Low Temperature ◽  
Epitaxial Growth ◽  
Growth Process ◽  
Growth Conditions ◽  
The Other ◽  
Additional Increase ◽  
Other Hand

In order to understand the influence of the Cl/Si ratio on the morphology of the low-temperature chloro-carbon epitaxial growth, HCl was added during the SiCl4/CH3Cl growth at 1300°C. Use of higher Cl/Si ratio allowed only modest improvements of the growth rate without morphology degradation, which did not go far beyond what has been achieved previously by optimizing the value of the input C/Si ratio. On the other hand, when the epitaxial growth process operated at too low or too high values of the input C/Si ratio, i.e., outside of the window of good epilayer morphology, any additional increase of the Cl/Si ratio caused improvement of the epilayer morphology. It was established that this improvement was due to a change of the effective C/Si ratio towards its intermediate values, which corresponded to more favorable growth conditions.

Effect of C/Si Ratio and Nitrogen Doping on 4H-SiC Epitaxial Growth Using Dichlorosilane Precursor

2015 ◽  
Vol 821-823 ◽  
pp. 129-132 ◽  
Author(s):  
Hai Zheng Song ◽  
M.V.S. Chandrashekhar ◽  
T.S. Sudarshan
Keyword(s):  
Growth Rate ◽  
Epitaxial Growth ◽  
Nitrogen Doping ◽  
Gas Flow ◽  
Gas Flow Rate ◽  
Wide Range ◽  
N Doping ◽  
Morphological Defects ◽  
Defect Densities ◽  
Epilayer Surface

Application of dichlorosilane (DCS) in 4H-SiC epitaxial growth on 4° off-cut substrates has been studied. The effect of C/Si ratio and N2gas flow rate on epilayer properties is investigated in detail. It is found that the C/Si ratio has a significant influence on the growth rate, epilayer surface roughness (step-bunching), conversion of basal plane dislocations (BPDs), and generation of morphological defects and in-grown stacking faults. A wide range of doping concentration from p- to n+ can be controlled in DCS growth. High quality 4° off-cut SiC epilayers are achieved for C/Si=1.3 – 1.8. Addition of N2has no obvious influence on growth rate and defect densities. The BPD conversion greater than 99.8% is achieved independent of N doping without any pretreatment.

scholarly journals Effects of MOVPE Growth Conditions on GaN Layers Doped with Germanium

2020 ◽  
Author(s):  
Dario Schiavon ◽  
Elżbieta Litwin-Staszewska ◽  
Rafał Jakieła ◽  
Szymon Grzanka ◽  
Piotr Perlin
Keyword(s):  
Growth Rate ◽  
High Temperature ◽  
Low Temperature ◽  
Surface Morphology ◽  
Growth Temperature ◽  
High Growth ◽  
Growth Conditions ◽  
High Growth Rate ◽  
Pit Formation ◽  
Movpe Growth

The effect of growth temperature and precursor flows on the doping level and surface morphology of Ge-doped GaN layers was researched. The results show that germanium is more readily incorporated at low temperature, high growth rate and high V/III ratio, thus revealing a similar behavior to what was previously observed for indium. V-pit formation can be blocked at high temperature but also at low V/III ratio, the latter of which however causing step bunching.

Developing and validating protocols for mechanical isolation of guard-cell enriched epidermal peels for omics studies

2020 ◽  
Vol 47 (9) ◽  
pp. 803
Author(s):  
Fatemeh Rasouli ◽  
Ali Kiani-Pouya ◽  
Heng Zhang ◽  
Sergey Shabala
Keyword(s):  
Gene Expression ◽  
Guard Cell ◽  
Critical Role ◽  
Guard Cells ◽  
Growth Conditions ◽  
Modified Technique ◽  
Isolation Technique ◽  
Rna Integrity ◽  
Wide Range ◽  
Mechanical Isolation

Stomata, which are microscopic valves on the leaf surface formed by two guard cells (GC), play a critical role in the regulation of leaf water and gas exchange and, hence, determine plant adaptive potential. However, little data is available on GC biochemistry, protein abundance and gene expression, mainly due to technical difficulties and challenges in isolating sufficient amounts of high-quality pure GC. In the present study we applied some modifications to the mechanical isolation of guard-cell to generalise this method for diverse growth conditions as well as plant species. Epidermal peel fragments enriched in guard cells were mechanically isolated from quinoa, spinach and sugar beet leaves grown at two conditions (normal and salt stress). Multiple analysis was performed to confirm the suitability and superiority of the modified technique to the original method. At the first step, the viability and purity of GC-enriched epidermal fragments were assessed under the microscope. Then, the RNA integrity, gene expression, and 1D SDS-PAGE tests were performed to validate the suitability of this technique for omics studies. The data revealed a wide range of proteins as well as a high integrity of RNA extracted from guard cell samples. The expression level of several GC-specific genes and mesophyll-dominant genes were investigated using a comparative analysis of transcriptome datasets of GC and whole-leaf samples. We found that Rubisco and photosynthesis-related proteins such as chlorophyll a/b binding protein were substantially higher in the whole leaf compared with the GCs. More importantly, GC-specific genes such as OST1, SLAC1, MYB60, FAMA and HT1 were highly expressed in the GCs, confirming that our guard cell preparation was highly enriched in GC gene transcripts. Real-time quantitative reverse transcription PCR further confirmed the efficacy of the GC isolation technique for exploring responses of GC to diverse types of stress at the molecular level.

Factors Influencing the Growth Rate, Doping, and Surface Morphology of the Low-Temperature Halo-Carbon Homoepitaxial Growth of 4H SiC with HCl Additive

2008 ◽  
Vol 1069 ◽  
Author(s):  
Galyna Melnychuk ◽  
Huang De Lin ◽  
Siva Prasad Kotamraju ◽  
Yaroslav Koshka
Keyword(s):  
Growth Rate ◽  
Low Temperature ◽  
Surface Morphology ◽  
Gas Flow ◽  
Flow Direction ◽  
Vapor Condensation ◽  
Homoepitaxial Growth ◽  
Factors Influencing ◽  
Silicon Vapor ◽  
Hot Zone

ABSTRACTIn this work, a possibility to further suppress silicon vapor condensation and formation of Si clusters in order to improve the growth rate and morphology during the low-temperature halo-carbon epitaxial growth of 4H-SiC was investigated. While a pronounced dissociating of Si clusters was clearly demonstrated, the enhancement of the growth rate and morphology was less significant then expected. In addition, the homogeneity of the growth rate and doping along the gas flow direction indicated that a significant and non-equal depletion of Si and C growth species takes place at sufficiently high HCl supply. HCl flow-dependent formation of polycrystalline Si and SiC deposits in the upstream portion of the hot zone was shown to be the source of this depletion.

A bio-inspired self-recoverable polyampholyte hydrogel with low temperature sensing

2021 ◽  
Author(s):  
Xinyao Li ◽  
Lingshu Kong ◽  
Guanghui Gao
Keyword(s):  
Low Temperature ◽  
Temperature Sensing ◽  
Physiological Signal ◽  
Electronic Skin ◽  
Wide Range ◽  
Temperature Environment ◽  
Stable Performance ◽  
Signal Monitoring ◽  
Complex Temperature

An anti-freezing, self-recovery sensor enabled by a polyampholyte hydrogel demonstrated stable performance in a complex temperature environment and exhibited a wide range of applications in physiological signal monitoring and electronic skin.

High Quality Uniform Thick Epitaxy of 4H-SiC for High Power Device Applications

2006 ◽  
Vol 911 ◽  
Author(s):  
Jie Zhang ◽  
Janice Mazzola ◽  
Esteban Romano ◽  
Carl Hoff ◽  
Mike Mazzola ◽  
...  
Keyword(s):  
Growth Rate ◽  
Low Temperature ◽  
Surface Morphology ◽  
Smooth Surface ◽  
Nitrogen Doping ◽  
Defect Density ◽  
Power Device ◽  
High Quality ◽  
Device Applications ◽  
Good Uniformity

AbstractGrowth of thick SiC epilayers has been investigated in a horizontal hot-wall CVD reactor capable of growing 3x2-in wafers or single wafer with a diameter up to 100mm. Good uniformity of lower than 3% for thickness and lower than 20% for doping has been obtained on 2-in or 3-in epi wafers with thickness of 60 - 120 μm. Low intentional nitrogen doping of 5.8x1014 cm-3 was achieved on a 3-in epi wafer with a thickness of 120 μm. A higher growth rate of 10 μm/h was achieved while good uniformity was maintained. Surface morphology of the thick epilayers was carefully examined and smooth surface was observed for epilayers thicker than 100 μm. The defect density of the thick epilayers was also discussed and the high purity of the thick epi was verified by low temperature PL measurement.

Growth responses of cultivars of subterranean clover to temperature, plant density and nitrate supply

1990 ◽  
Vol 41 (1) ◽  
pp. 101 ◽  
Author(s):  
JH Silsbury ◽  
TW Hancock
Keyword(s):  
Growth Rate ◽  
Low Temperature ◽  
Plant Density ◽  
Subterranean Clover ◽  
Growth Conditions ◽  
High Density ◽  
Growth Responses ◽  
Mineral N ◽  
Nitrate Supply ◽  
Temperature Interaction

Six cultivars of subterranean clover were compared for growth as swards under controlled conditions in six separate experiments. Conditions common to all experiments were: 400 8mol quanta m-2 s-1 and 12 h day: 12 h night. The variable regimens were: 2 000 or 12 000 plants m-2 ('low' and 'high' density), 10 to 20�C; and no mineral N (0 mM) or N supplied as a 7.5 mM NO3- solution. Growth responses to these conditions were tested by sequential harvesting for dry matter and the fitting of linear and quadratic regression models. Special attention was given to testing for differential responses by cultivars to temperature. All cultivars except 'Woogenellup' grew about 20% faster when NO3- was supplied in the nutrient solution than when the N was derived entirely from N2 fixation under the 0mM treatment. Crop growth rate at 20�C was about double that at 10�C at low density, but at high density the rate at 20�C was 90-95% of that at 10�C. Cultivars differed significantly in growth rate but over all conditions, there was a hierarchical order from the highest to the lowest of: 'Clare', 'Woogenellup', 'Yarloop', 'Mt. Barker', 'Daliak' and 'Geraldton'. There was very little evidence of any cultivar by temperature interaction except for 'Woogenellup, which responded to a low temperature of 10�C compared with a 'high' of 20�C better than the other cultivars. The importance of seed size as a factor influencing the early growth of a subterranean clover sward was emphasized where swards established from large seeds of 'Mt. Barker' grew faster than where small seeds were used. 'Clare' was a highly productive cultivar under all growth conditions. It is concluded that the growth rates of swards of subterranean clover established at seedling densities in excess of 5000 plants m-2 are less sensitive to a low temperature of 10�C than are those established at more conventional densities.

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