Growths of AlInN Single Layers and Distributed Bragg Reflectors for VCSELs

2015 ◽  
Vol 1736 ◽  
Author(s):  
Y. Kozuka ◽  
K. Ikeyama ◽  
T. Yasuda ◽  
T. Takeuchi ◽  
S. Kamiyama ◽  
...  
Keyword(s):  
Smooth Surface ◽  
Growth Parameters ◽  
Mixing Time ◽  
High Growth ◽  
Growth Conditions ◽  
High Growth Rate ◽  
Smooth Surfaces ◽  
Bragg Reflectors ◽  
Distributed Bragg Reflectors ◽  
Movpe Growth

ABSTRACTWe investigated MOVPE growth conditions for AlInN layers with high growth rates and obtained 0.5µm/h with smooth surfaces. We found that short gas mixing time, relatively high growth temperature, and very low In/Al supply ratio were key growth parameters in order to obtain the AlInN layers with high growth rate and smooth surface simultaneously. AlInN/GaN DBRs grown under such growth conditions showed smooth surfaces and a reflectivity of over 99%.

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.

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

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 354
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 flow 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.

Emission characteristics of GaInN/GaN multiple quantum shell nanowire-based LEDs with different p-GaN growth conditions

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sae Katsuro ◽  
Weifang Lu ◽  
Kazuma Ito ◽  
Nanami Nakayama ◽  
Naoki Sone ◽  
...  
Keyword(s):  
Growth Rate ◽  
Shell Growth ◽  
Light Output ◽  
High Growth ◽  
Growth Conditions ◽  
High Growth Rate ◽  
Current Injection ◽  
Emission Characteristics ◽  
Multiple Quantum ◽  
Plane Region

Abstract Improving current injection into r- and m-planes of nanowires (NWs) is essential to realizing efficient GaInN/GaN multiple quantum shell (MQS) NW-based light-emitting diodes (LEDs). Here, we present the effects of different p-GaN shell growth conditions on the emission characteristics of MQS NW-LEDs. Firstly, a comparison between cathodoluminescence (CL) and electroluminescence (EL) spectra indicates that the emission in NW-LEDs originates from the top region of the NWs. By growing thick p-GaN shells, the variable emission peak at around 600 nm and degradation of the light output of the NW-LEDs are elaborated, which is attributable to the localization of current in the c-plane region with various In-rich clusters and deep-level defects. Utilizing a high growth rate of p-GaN shell, an increased r-plane and a reduced c-plane region promote the deposition of indium tin oxide layer over the entire NW. Therefore, the current is effectively injected into both the r- and m-planes of the NW structures. Consequently, the light output and EL peak intensity of the NW-LEDs are enhanced by factors of 4.3 and 13.8, respectively, under an injection current of 100 mA. Furthermore, scanning transmission electron microscope images demonstrate the suppression of dislocations, triangular defects, and stacking faults at the apex of the p-GaN shell with a high growth rate. Therefore, localization of current injection in nonradiative recombination centers near the c-plane was also inhibited. Our results emphasize the possibility of realizing high efficacy in NW-LEDs via optimal p-GaN shell growth conditions, which is quite promising for application in the long-wavelength region.

Heteroepitaxy of Si, Ge, and GaAs Films on CaF2/Si Structures

1986 ◽  
Vol 67 ◽  
Author(s):  
H. Ishiwara ◽  
T. Asano ◽  
H. C. Lee ◽  
Y. Kuriyama ◽  
K. Seki ◽  
...  
Keyword(s):  
Smooth Surface ◽  
Field Effect Transistors ◽  
Growth Parameters ◽  
Growth Conditions ◽  
Heteroepitaxial Growth ◽  
Gate Electrodes ◽  
Gaas Films ◽  
Temperature And Growth ◽  
Si Films

ABSTRACTRecent progress in the research of heteroepitaxial growth of Si, Ge, and GaAs films on CaF2/Si structures is reviewed. Growth conditions and material properties of the Si/CaF2/Si structures are first discussed. It is shown that such growth techniques as the predeposition technique and the recrystallization method are useful to improve the crystalline quality of Si films on the CaF2/Si structures. Then, device application of the Si/CaF2/Si structure to field effect transistors with epitaxial MIS (metal-insulatorsemiconductor) gate electrodes is described. Finally, epitaxial growth of Ge and GaAs films on the CaF2/Si structure are discussed, in which such growth parameters as the substrate temperature and growth rate are optimized to obtain high-quality films with excellent crystallinity and smooth surface.

scholarly journals Growth dynamic on a co-cultivation of two Chlorophyta microalgae exposed to copper

2021 ◽  
Vol 33 ◽  
Author(s):  
Rafael Barty Dextro
Keyword(s):  
Growth Parameters ◽  
Copper Toxicity ◽  
High Growth ◽  
Single Species ◽  
High Growth Rate ◽  
Toxic Agent ◽  
Continuous Increase ◽  
Essential Nutrient ◽  
Unialgal Culture ◽  
Great Relevance

Abstract: Aim Copper is an essential nutrient for the phytoplankton, but it can also act as a toxic agent, depending on its concentration. Considering the continuous increase of this metal in the natural aquatic ecosystems, understanding its actions in co-cultivation scenarios is of great relevance. Experiments with the combination of different species resemble more accurately the natural conditions, in contrast of results obtained in single-species tests, which cannot be directly used to describe observed effects on the environment. Methods Therefore, growth parameters were investigated and compared on the co-cultivation of Chlorella sorokiniana and Kirchneriella obesa and their separate cultures exposed to three different free copper concentrations (control 6x10-9, intermediate 2x10-7 and high 1.5x10-6 mol.L-1 Cu2+). Results C. sorokiniana registered more cells in the control of the unialgal culture while K. obesa had higher cell density in the control of the co-cultivation. Growth rates decreased with the increment of copper in the unialgal conditions. However, both species maintained a high growth rate in the co-cultivation intermediate copper concentrations. Biovolume varied despite the cultivation method, being strongly related to the metal’s concentration. The maximum photosynthetic efficiency decreased in higher copper. Conclusions According to the results observed, no competitive exclusion occurred and both species were affected by copper in unialgal and co-cultivation conditions, with K. obesa being favored by the co-cultivation, which seems to have an attenuation effect on copper toxicity until intermediate concentrations. Ecologically, the results suggest that communities deal better with the toxic effects caused by intermediate copper concentrations than single-species cultures.

scholarly journals Growth parameters estimates for a small fish of the Pantanal, Brazil: Moenkhausia dichroura (Characiformes; Characidae)

2007 ◽  
Vol 67 (2) ◽  
pp. 293-297 ◽  
Author(s):  
NL. Cunha ◽  
AC. Catella ◽  
MA. Kinas
Keyword(s):  
Standard Length ◽  
Growth Parameters ◽  
Economic Value ◽  
High Growth ◽  
Aquatic Organisms ◽  
High Growth Rate ◽  
Small Fish ◽  
Important Species ◽  
Mato Grosso ◽  
Tropical Environments

Growth parameters were estimated for Moenkhausia dichroura (Kner, 1858) (Characiformes, Characidae), a small-sized and very abundant fish of the Pantanal lentic habitats commonly known as "pequira ". A method based on the length frequencies distribution and the ELEFAN I routine from the FISAT program were used. The fish were collected in the Baia da Onça, an oxbowlake of the sub-region Pantanal of Aquidauana, Mato Grosso do Sul, Brazil, from June to December 1988. The standard length of the captured fishes ranged from 29 to 76 mm with an average of 53 mm. The estimated growth parameters were L<FONT FACE=Symbol>¥</FONT> = 81 mm (standard length), k = 0.85 year-1, C = 0.89, WP = 0.6 (Rn = 0.285). The WP indicated that growth reduction occurred in July, when the lowest temperature of the year was registered. The growth curve showed that captured individuals belonged to three cohorts. The obtained results seem robust and quite compatible with the biology of the fish and its adjustment to the environment. M. dichroura, in spite of not being a direct fishing interest, is an important species in terms of its ecological aspects, due to its abundance and high growth rate, and as a great food source for aquatic organisms and specially for larger fish of economic value. Considering the information gap about small fish, the parameters estimated for pequira constitute a comparison base for other growth studies of small-sized fish species of tropical environments.

Structure Evolution of 3C-SiC on Cubic and Hexagonal Substrates

2006 ◽  
Vol 527-529 ◽  
pp. 283-286 ◽  
Author(s):  
Rositza Yakimova ◽  
Gholam Reza Yazdi ◽  
Nut Sritirawisarn ◽  
Mikael Syväjärvi
Keyword(s):  
Initial Temperature ◽  
High Growth ◽  
Growth Conditions ◽  
High Growth Rate ◽  
Good Choice ◽  
Structure Evolution ◽  
Bulk Crystals ◽  
Initial Formation ◽  
Temperature Ramp ◽  
Thick Layers

We report on growth of 3C-SiC by sublimation process in vacuum with the aim to ultimately select conditions for single polytype growth of bulk crystals. The 3C polytype occurrence, growth mechanism and structure evolution have been in the focus of the study. To gain understanding of the initial formation of the cubic polytype, growth was performed on various substrates, such as 6H- and 4H-SiC (on-axis and vicinal), as well as freestanding 3C-SiC wafers. The growth configuration used allowed a high growth rate, e.g. up to 200 (m/h, respectively very thick layers. The grown material was studied by means of optical microscopy, AFM and HRTEM. 6H-SiC (0001) Si-face substrates may be a good choice if the 3C nucleation is well controlled, which can be achieved by selecting the initial temperature ramp up and substrate orientation. These growth conditions limit the number of nucleation centers and decrease the defective boundaries.

scholarly journals COMPARATIVE ANALYSIS OF AROMA PROPERTIES OF Pleurotus ostreatus INDUSTRIAL STRAINS

2019 ◽  
Vol 2 (4) ◽  
pp. 28-31
Author(s):  
Ekaterina Vlasenko ◽  
Olga Kuznetsova ◽  
Alexander Matrosov
Keyword(s):  
Pleurotus Ostreatus ◽  
Growth Parameters ◽  
Profile Analysis ◽  
High Growth ◽  
High Growth Rate ◽  
Sensory Profile ◽  
Important Criterion ◽  
Industrial Strains ◽  
Hexane Extracts ◽  
Selection Of

Flavor properties of mushrooms are an important criterion that determines the selection of strains for industrial cultivation. The purpose of the study was to determine growth parameters and aroma profile of six most common industrial Pleurotus ostreatus (Jacq.) P. Kumm. strains in the process of intensive cultivation on sunflower husk. To achieve this purpose, methods of sensory profile analysis and ultraviolet spectroscopy were used.Sensory profile analysis of flavor showed that fruit bodies of the IBK-1535 and IBK-1543 strains had the highest intensity of the mushroom note of aroma.Spectrophotometric analysis demonstrated that mushroom hexane extracts had light absorption maxima in the ranges of 207-210 nm and of 250-290 nm. Thus, the spectrum of the strain IBK-1535 had the highest intensity in the whole range of wavelengths.The screening of P. ostreatus strains allows us to recommend the IBK-1535 and IBK-1543 strains, which have a high growth rate and productivity, as well as the most pronounced characteristic mushroom aroma, for industrial cultivation.

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