Effects of growth temperature on photosynthetic gas exchange characteristics and hydraulic anatomy in leaves of two cold-climate Poa species

2011 ◽  
Vol 38 (1) ◽  
pp. 54 ◽  
Author(s):  
Danielle E. Medek ◽  
John R. Evans ◽  
Marcus Schortemeyer ◽  
Marilyn C. Ball
Keyword(s):  
Growth Temperature ◽  
Photosynthetic Capacity ◽  
Vascular Anatomy ◽  
Growth Conditions ◽  
Cold Climate ◽  
Photosynthetic Gas Exchange ◽  
Interspecific Differences ◽  
Summer Temperatures ◽  
Gas Exchange Characteristics ◽  
Nitrogen Contents

How plastic is hydraulic anatomy with growth temperature, and how does this relate to photosynthesis? These interrelationships were studied in subantarctic Poa foliosa Hook. f. and alpine Poa hothamensis Vickery grown under 7/4°C and 12/9°C day/night temperatures, reflecting summer temperatures in their respective habitats. Conduit radii were smaller in P. foliosa than in P. hothamensis, consistent with greater avoidance of freeze/thaw-induced embolism. Despite its origins in an environment with relatively little temperature variation, P. foliosa exhibited greater plasticity in hydraulic anatomy than P. hothamensis, increasing the size and density of conduits when grown under the warmer temperature regime. Both species had similar anatomical capacities for water transport when grown at 12/9°C, but stomatal conductance was lower in P. foliosa than P. hothamensis, suggesting hydraulic limitations not explained by leaf vascular anatomy. However, greater photosynthetic capacity and foliar nitrogen contents enabled P. foliosa to achieve the same assimilation rate as P. hothamensis under the 12/9°C growth conditions. Our results showed that nitrogen plays a central role in maintaining assimilation rates when constrained either by enzymatic activity at low temperatures or by hydraulic limitations at high temperatures and evaporative demands. Interspecific differences in nitrogen and water use may influence how subantarctic and alpine vegetation responds to climate warming.

Strain in 3C–SiC Heteroepitaxial Layers Grown on (100) and (111) Oriented Silicon Substrates

2008 ◽  
Vol 600-603 ◽  
pp. 207-210 ◽  
Author(s):  
Marcin Zielinski ◽  
Marc Portail ◽  
Thierry Chassagne ◽  
Yvon Cordier
Keyword(s):  
Gaseous Phase ◽  
Growth Temperature ◽  
Growth Conditions ◽  
Silicon Substrates ◽  
Phase Growth ◽  
Growth Duration ◽  
Strain Control ◽  
Heteroepitaxial Layers ◽  
Oriented Layers ◽  
Sic Films

We discuss the influence of the growth conditions (composition of the gaseous phase, growth duration, growth temperature) and wafer properties (orientation, miscut, thickness) on the residual strain of 3C-SiC films grown on silicon substrates. We show that the strain related effects are observed for both studied orientations however some of them (namely the creep effects) were up to now stated only for (100) oriented layers. We also point out the main difference in strain control between the (111) and (100) orientations.

scholarly journals Characterisation of III?V Multilayers Grown by Low-pressure Metal Organic Vapour-phase Epitaxy

1993 ◽  
Vol 46 (3) ◽  
pp. 435
Author(s):  
C Jagadish ◽  
A Clark ◽  
G Li ◽  
CA Larson ◽  
N Hauser ◽  
...  
Keyword(s):  
Gallium Arsenide ◽  
Growth Temperature ◽  
Deep Level ◽  
Growth Parameters ◽  
Low Pressure ◽  
Vapour Phase ◽  
Growth Conditions ◽  
Vapour Phase Epitaxy ◽  
Metal Organic ◽  
Organic Vapour

Undoped and doped layers of gallium arsenide and aluminium gallium arsenide have been grown on gallium arsenide by low-pressure metal organic vapour-phase epitaxy (MOVPE). Delta doping and growth on silicon substrates have also been attempted. Of particular interest in the present study has been the influence of growth parameters, such as growth temperature, group III mole fraction and dopant flow, on the electrical and physical properties of gallium arsenide layers. An increase in growth temperature leads to increased doping efficiency in the case of silicon, whereas the opposite is true in the case of zinc. Deep level transient spectroscopy (DTLS) studies on undoped GaAs layers showed two levels, the expected EL2 level and a carbon-related level. The determination of optimum growth conditions has allowed good quality GaAs and AlGaAs epitaxial layers to be produced for a range of applications.`

4H-SiC Homoepitaxial Growth on Vicinal-Off Angled Si-Face Substrate

2010 ◽  
Vol 645-648 ◽  
pp. 99-102 ◽  
Author(s):  
Kazutoshi Kojima ◽  
Sachiko Ito ◽  
Junji Senzaki ◽  
Hajime Okumura
Keyword(s):  
Surface Morphology ◽  
Epitaxial Growth ◽  
Growth Temperature ◽  
Growth Conditions ◽  
Step Bunching ◽  
Homoepitaxial Growth ◽  
Blocking Voltage ◽  
Basal Plane Dislocation ◽  
Epilayer Surface

We have carried out detailed investigations of 4H-SiC homoepitaxial growth on vicinal off-angled Si-face substrates. We found that the surface morphology of the substrate just after in-situ H2 etching was also affected by the value of the vicinal-off angle. Growth conditions consisting of a low C/Si ratio and a low growth temperature were effective in suppressing macro step bunching at the grown epilayer surface. We also demonstrated epitaxial growth without step bunching on a 2-inch 4H-SiC Si-face substrate with a vicinal off angle of 0.79o. Ni Schottky barrier diodes fabricated on an as-grown epilayer had a blocking voltage above 1000V and a leakage current of less than 5x10-7A/cm2. We also investigated the propagation of basal plane dislocation from the vicinal off angled substrate into the epitaxial layer.

Impact of Buffered Layer Growth Conditions on Grown-In Vacancy Concentrations in Molecular Beam Epitaxy Silicon Germanium

2004 ◽  
Vol 809 ◽  
Author(s):  
Kareem M. Shoukri ◽  
Yaser M. Haddara ◽  
Andrew P. Knights ◽  
Paul G. Coleman ◽  
Mohammad M. Rahman ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Buffer Layer ◽  
Point Defects ◽  
Growth Temperature ◽  
Silicon Germanium ◽  
Molecular Beam ◽  
Growth Conditions ◽  
Layer Growth ◽  
Vacancy Clusters ◽  
Temperature And Growth

ABSTRACTSilicon-Germanium (SiGe) has become increasingly attractive to semiconductor manufacturers over the last decade for use in high performance devices. In order to produce thin layers of device grade SiGe with low concentrations of point defects and well-controlled doping profiles, advanced growth and deposition techniques such as molecular beam epitaxy (MBE) are used. One of the key issues in modeling dopant diffusion during subsequent processing is the concentration of grown-in point defects. The incorporation of vacancy clusters and vacancy point defects in 200nm SiGe/Si layers grown by molecular beam epitaxy over different buffer layers has been observed using beam-based positron annihilation spectroscopy. Variables included the type of buffer layer, the growth temperature and growth rate for the buffer, and the growth temperature and growth rate for the top layer. Different growth conditions resulted in different relaxation amounts in the top layer, but in all samples the dislocation density was below 106 cm−2. Preliminary results indicate a correlation between the size, type and concentration of vacancy defects and the buffer layer growth temperature. At high buffer layer growth temperature of 500°C the vacancy point defect concentration is below the PAS detectable limit of approximately 1015 cm−3. As the buffer layer growth is decreased to a minimum value of 300°C, large vacancy clusters are observed in the buffered layer and vacancy point defects are observed in the SiGe film. These results are relevant to the role played by point defects grown-in at temperatures below ∼350°C in modeling dopant diffusion during processing.

Photosynthetic capacity of tropical montane tree species in relation to leaf nutrients, successional strategy and growth temperature

Oecologia ◽  
2015 ◽  
Vol 177 (4) ◽  
pp. 1183-1194 ◽  
Author(s):  
Mirindi Eric Dusenge ◽  
Göran Wallin ◽  
Johanna Gårdesten ◽  
Felix Niyonzima ◽  
Lisa Adolfsson ◽  
...  
Keyword(s):  
Growth Temperature ◽  
Tree Species ◽  
Photosynthetic Capacity ◽  
Leaf Nutrients

Electrical And Structural Properties Of LT-GaAs: Influence Of As/Ga Flux Ratio And Growth Temperature

1996 ◽  
Vol 442 ◽  
Author(s):  
M. Luysberg ◽  
H. Sohn ◽  
A. Prasad ◽  
P. Specht ◽  
H. Fujioka ◽  
...  
Keyword(s):  
Structural Properties ◽  
Point Defects ◽  
Growth Temperature ◽  
Conduction Mechanism ◽  
Growth Parameters ◽  
Flux Ratio ◽  
Growth Conditions ◽  
High Resistivity ◽  
Antisite Defects ◽  
Band Conduction

AbstracThe deposition of GaAs by MBE at low temperatures results in a material of unique properties. However, up to now the control and understanding of the electrical and structural properties are unsatisfactory. To investigate the influence of growth parameters on the formation of point defects and electrical properties, the substrate temperature and the As/Ga flux ratio were systematically varied. In a well defined parameter range the lattice expansion was found to be dominated by the formation of As antisite defects. After annealing a high resistivity is obtained independent of the growth conditions. A strong influence of the growth temperature on the band conduction mechanism is observed, whereas a variation of the As/Ga flux ratio induces only slight changes of the temperature dependence of the conductivity.

Electro-optic Mach-Zehnder modulators with polycrystalline BaTiO3 thin films on MgO

2002 ◽  
Vol 748 ◽  
Author(s):  
A. Petraru ◽  
J. Schubert ◽  
M. Schmid ◽  
O. Trithaveesak ◽  
Ch. Buchal
Keyword(s):  
Thin Films ◽  
Growth Temperature ◽  
Ion Beam ◽  
Growth Conditions ◽  
Propagation Loss ◽  
Ion Beam Etching ◽  
Waveguide Propagation ◽  
Electro Optic ◽  
Ridge Waveguides ◽  
Waveguide Modulators

ABSTRACTThe optical and electro-optical properties of epitaxially grown thin films of ferroelectric BaTiO3 on MgO substrates have been established and high quality Mach-Zehnder waveguide modulators have been demonstrated. As a next step towards the integration of ferroelectric thin films on different substrates, we have modified the growth conditions by lowering the growth temperature to study polycrystalline, but still highly transparent BaTiO3 (BTO) films. Polycrystalline BTO on MgO substrates has been grown by pulsed laser deposition (PLD). The growth temperature was reduced from 800 °C to 400 °C at an oxygen pressure of 2×10-3 mbar. Although polycrystalline, the BTO is still birefringent with no= 2.32 and ne = 2.30. Ridge waveguides have been formed by ion beam etching. The estimated waveguide propagation loss is 4 dB/cm at 633 nm. Electro-optic Mach-Zehnder modulators have been realized. Using 3 mm long electrodes with a spacing of 10 μm, a Vπ voltage of 14 V was obtained at 633 nm wavelength. This is half of the observed effective electro-optic coefficient measured at epitaxial BTO films. At 1.5 μm wavelength similar results were observed.

Optimal growth temperature for the isolation of Plesiomonas shigelloides, using various selective and differential agars

1991 ◽  
Vol 37 (10) ◽  
pp. 800-802 ◽  
Author(s):  
Anwarul Huq ◽  
Anwari Akhtar ◽  
M. A. R. Chowdhury ◽  
David A. Sack
Keyword(s):  
Growth Temperature ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Aeromonas Species ◽  
Growth Media ◽  
Optimal Growth Temperature ◽  
Environmental Waters ◽  
Temperature Growth ◽  
Plesiomonas Shigelloides ◽  
Incubation Temperatures

The growth characteristics of known strains of Plesiomonas shigelloides were compared with those of Aeromonas species (the major competing species in environmental waters) on plesiomonas differential agar, inositol brilliant green bile salt, and modified salmonella–shigella agar at incubation temperatures of 37, 42, and 44 °C. Using local isolates from clinical and environmental sources, optimal growth conditions, as determined by colony counts and the colony characteristics, plesiomonas differential agar proved to be ideal when incubated at 44 °C. Contrary to earlier recommendations for 48 h incubation, the colonies could be recognized readily after an incubation of 24 h. Key words: Plesiomonas, growth temperature, growth media.

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