Study of Grown-In Defects Verses Growth Parameters in GaAs and Al(x)Ga(1-x)AS Epitaxial Films Grown by LPE and MOCVD Techniques.

1985 ◽  
Author(s):  
Sheng S. Li
Keyword(s):  
Growth Parameters ◽  
Epitaxial Films

Precipitation in Al + 4% Cu Epitaxial Films

1968 ◽  
Vol 26 ◽  
pp. 384-385
Author(s):  
S. Herd ◽  
S. M. Mader
Keyword(s):  
Solid Solution ◽  
Bulk Material ◽  
Epitaxial Films ◽  
Detectable Change ◽  
Cu Films ◽  
Solution Treated ◽  
Single Crystal Films ◽  
Crystal Films ◽  
Diffraction Patterns ◽  
Deposited Films

Single crystal films in (001) orientation, about 1500 Å thick, were produced by R-F sputtering of Al + 4 wt % Cu onto cleaved KCl at 150°C substrate temperature. The as-deposited films contained numerous θ-CuAl2 particles (C16 structure) about 0.1μ in size. They were transferred onto Mo screens, solution treated and rapidly cooled (within about ½ min) so as to retain a homogeneous solid solution. Subsequently, the films were aged in vacuum at various temperatures in order to induce precipitation and to compare structures and morphologies of precipitate particles in Al-Cu films with those found in age hardened bulk material.Aging for 3 weeks at 60°C or 48 hrs at 100°C did not produce any detectable change in high resolution micrographs or diffraction patterns. In this range Guinier-Preston zones (GP) form in quenched bulk material. The absence of GP in the present experiments in this aging range is perhaps due to the cooling rate employed, which might be more equivalent to an aged and reverted bulk material than to a quenched one.

Epitaxial growth manner and structure of superconducting oxide films

1990 ◽  
Vol 48 (4) ◽  
pp. 2-3
Author(s):  
Yoshichika Bando ◽  
Takahito Terashima ◽  
Kenji Iijima ◽  
Kazunuki Yamamoto ◽  
Kazuto Hirata ◽  
...  
Keyword(s):  
Ultrathin Films ◽  
Film Surface ◽  
High Energy ◽  
Epitaxial Films ◽  
Layer By Layer ◽  
Initial Growth ◽  
In Situ Growth ◽  
High Quality ◽  
Activated Reactive Evaporation

The high quality thin films of high-Tc superconducting oxide are necessary for elucidating the superconducting mechanism and for device application. The recent trend in the preparation of high-Tc films has been toward “in-situ” growth of the superconducting phase at relatively low temperatures. The purpose of “in-situ” growth is to attain surface smoothness suitable for fabricating film devices but also to obtain high quality film. We present the investigation on the initial growth manner of YBCO by in-situ reflective high energy electron diffraction (RHEED) technique and on the structural and superconducting properties of the resulting ultrathin films below 100Å. The epitaxial films have been grown on (100) plane of MgO and SrTiO, heated below 650°C by activated reactive evaporation. The in-situ RHEED observation and the intensity measurement was carried out during deposition of YBCO on the substrate at 650°C. The deposition rate was 0.8Å/s. Fig. 1 shows the RHEED patterns at every stage of deposition of YBCO on MgO(100). All the patterns exhibit the sharp streaks, indicating that the film surface is atomically smooth and the growth manner is layer-by-layer.

Studies of Ge/Si(100) and Observation of Atomic Steps on Si(100) using Biassed Secondary Electron Imaging in a UHV STEM

1990 ◽  
Vol 48 (1) ◽  
pp. 308-309
Author(s):  
Mohan Krishnamurthy ◽  
Jeff S. Drucker ◽  
John A. Venablest
Keyword(s):  
Secondary Electron ◽  
Critical Thickness ◽  
Surface Defects ◽  
Film Growth ◽  
Growth Parameters ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Surface Steps ◽  
Epitaxial Crystal Growth ◽  
Electron Imaging

Secondary Electron Imaging (SEI) has become a useful mode of studying surfaces in SEM[1] and STEM[2,3] instruments. Samples have been biassed (b-SEI) to provide increased sensitivity to topographic and thin film deposits in ultra high vacuum (UHV)-SEM[1,4]; but this has not generally been done in previous STEM studies. The recently developed UHV-STEM ( codenamed MIDAS) at ASU has efficient collection of secondary electrons using a 'parallelizer' and full sample preparation system[5]. Here we report in-situ deposition and annealing studies on the Ge/Si(100) epitaxial system, and the observation of surface steps on vicinal Si(100) using b-SEI under UHV conditions in MIDAS.Epitaxial crystal growth has previously been studied using SEM and SAM based experiments [4]. The influence of surface defects such as steps on epitaxial growth requires study with high spatial resolution, which we report for the Ge/Si(100) system. Ge grows on Si(100) in the Stranski-Krastonov growth mode wherein it forms pseudomorphic layers for the first 3-4 ML (critical thickness) and beyond which it clusters into islands[6]. In the present experiment, Ge was deposited onto clean Si(100) substrates misoriented 1° and 5° toward <110>. This was done using a mini MBE Knudsen cell at base pressure ~ 5×10-11 mbar and at typical rates of 0.1ML/min (1ML =0.14nm). Depositions just above the critical thickness were done for substrates kept at room temperature, 375°C and 525°C. The R T deposits were annealed at 375°C and 525°C for various times. Detailed studies were done of the initial stages of clustering into very fine (∼1nm) Ge islands and their subsequent coarsening and facetting with longer anneals. From the particle size distributions as a function of time and temperature, useful film growth parameters have been obtained. Fig. 1 shows a b-SE image of Ge island size distribution for a R T deposit and anneal at 525°C. Fig.2(a) shows the distribution for a deposition at 375°C and Fig.2(b) shows at a higher magnification a large facetted island of Ge. Fig.3 shows a distribution of very fine islands from a 525°C deposition. A strong contrast is obtained from these islands which are at most a few ML thick and mottled structure can be seen in the background between the islands, especially in Fig.2(a) and Fig.3.

Evaluation of Azadirachtin on Arthrospira plantensis Gomont growth parameters and antioxidant enzymes

2020 ◽  
Vol 56 ◽  
pp. 8
Author(s):  
Hatice Tunca ◽  
Ali Doğru ◽  
Feray Köçkar ◽  
Burçin Önem ◽  
Tuğba Ongun Sevindik
Keyword(s):  
Enzyme Activity ◽  
Growth Parameters ◽  
Arthrospira Platensis ◽  
Proline Content ◽  
Enzyme Analysis ◽  
Free Proline ◽  
Sod Activity ◽  
Pesticide Pollution ◽  
Antioxidant Parameters ◽  
Mda Content

Azadirachtin (Aza) used as insecticide due to inhibiting growth of insects and preventing them from feeding on plants. To understand the effects of contamination of this insecticide on phototrophs, and to determine the responses of these organisms against these insecticides are extremely important in understanding how the ecosystem is affected. In this study, chlorophyll-a amount, OD 560 and antioxidant parameters (total SOD, APX, GR, Proline, MDA and H2O2) were determined in order to understand the effect of Aza on Arthrospira platensis Gomont. Aza was applied between 0–20 μg mL−1 concentrations for 7 days in the study. Enzyme analysis was conducted at the end of the 7th day. There was a statistically significant decrease in the absorbance of OD560 and the chlorophyll-a content in A. platensis cultures exposed to the Aza (0–20 μg mL−1) during 7 days due to the increase in pesticide levels. SOD activity decreased at 8, 16 and 20 μg mL−1 concentrations; GR enzyme activity showed a significant decrease compared to the control at a concentration of 20 μg mL−1. APX activity did not change significantly compared to control. The MDA content increased significantly at 16 and 20 μg mL−1 concentrations. The H2O2 content significantly increased at 12, 16 and 20 μg mL−1 concentrations (p < 0.05) while the free proline content decreased at 4 μg mL−1 concentration (p < 0.05). As a result, regarding the Aza concentrations used in this study may be a step to prevent pesticide pollution in the environment.

Ion Beam Sputter Deposition Of Ferroelectric Oxide Thin Films

1991 ◽  
Vol 223 ◽  
Author(s):  
Thomas M. Graettinger ◽  
O. Auciello ◽  
M. S. Ameen ◽  
H. N. Al-Shareef ◽  
K. Gifford ◽  
...  
Keyword(s):  
Thin Films ◽  
Lead Zirconate Titanate ◽  
Growth Parameters ◽  
Ion Beam ◽  
Lead Zirconate ◽  
Electro Optic ◽  
Integrated Optical ◽  
Pzt Films ◽  
Ion Beam Sputter Deposition ◽  
Ferroelectric Oxide

ABSTRACTFerroelectric oxide films have been studied for their potential application as integrated optical materials and nonvolatile memories. Electro-optic properties of potassium niobate (KNbO3) thin films have been measured and the results correlated to the microstructures observed. The growth parameters necessary to obtain single phase perovskite lead zirconate titanate (PZT) thin films are discussed. Hysteresis and fatigue measurements of the PZT films were performed to determine their characteristics for potential memory devices.

In-depth Analysis of the Impurities in GaN

1996 ◽  
Vol 1 ◽  
Author(s):  
A. P. Kovarsky ◽  
V. S. Strykanov
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Dynamic Range ◽  
Detection Limits ◽  
Background Level ◽  
Epitaxial Films ◽  
Depth Analysis ◽  
Lower Detection ◽  
Minimum Detection Level ◽  
Ion Yields ◽  
Secondary Ion

GaN epitaxial films were analyzed by Secondary Ion Mass Spectrometry (SIMS). Standard implanted samples were used to determine the appropriate analytical conditions for analysis of impurities. The dose and energy of implantation for selected elements (Mg, Al, Si, Zn, Cd, H, C and O) were chosen so the maximum impurity concentration was not more than 1020 atoms/cm3. The optimum analysis conditions were ascertained from the standards for each element, and the detection limits were deduced from the background levels of the implantation profiles. We demonstate that lower detection limits of 1015 atoms/cm3 with a dynamic range 103 − 105 are possible. Zn and Cd have low ion yields, so the minimum detection level for these elements is the background level of the detector. The detection limits of the other elements are determined by the contamination of an initial GaN matrix.

Growth of Dracaena marginata and Spathiphyllum ‘Petite’ in Sphagnum Peat- and Coconut Coir Dust-based Growing Media

1999 ◽  
Vol 17 (1) ◽  
pp. 49-52 ◽  
Author(s):  
Robert H. Stamps ◽  
Michael R. Evans
Keyword(s):  
Growth Parameters ◽  
Cocos Nucifera ◽  
Greenhouse Production ◽  
Growing Media ◽  
Sphagnum Peat ◽  
Affected Plant ◽  
Coir Dust ◽  
Media Component ◽  
The Media ◽  
Cocos Nucifera L

Abstract A comparison was made of Canadian sphagnum peat (SP) and Philippine coconut (Cocos nucifera L.) coir dust (CD) as growing media components for greenhouse production of Dracaena marginata Bak. and Spathiphyllum Schott ‘Petite’. Three soilless foliage plant growing mixes (Cornell, Hybrid, University of Florida #2 [UF-2]) were prepared using either SP or CD and pine bark (PB), vermiculite (V), and/or perlite (P) in the following ratios (% by vol): Cornell = 50 CD or SP:25 V:25 P, Hybrid = 40 CD or SP:30 V:30 PB, UF-2 = 50 CD or SP: 50 PB. Dracaena root growth was not affected by treatments but there were significant mix × media component interactions that affected plant top growth parameters. In general, the growth and quality of D. marginata were reduced by using CD in Cornell, had no effect in Hybrid, and increased in UF-2. S. ‘Petite’ grew equally well in all growing mixes regardless of whether CD or SP was used; however, plants grew more in Cornell and Hybrid than in UF-2. S. ‘Petite’ roots, which were infested with Cylindrocladium spathiphylli, had higher grades when grown in CD than when the media contained SP.

The effects and mechanisms of acids on the health of piglets and weaners – a review

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Piotr Nowak ◽  
Anita Zaworska-Zakrzewska ◽  
Andrzej Frankiewicz ◽  
Małgorzata Kasprowicz-Potocka
Keyword(s):  
Digestive System ◽  
Buffer Capacity ◽  
Growth Parameters ◽  
Feed Additives ◽  
Feed Additive ◽  
Growth Promoters ◽  
Qualitative And Quantitative ◽  
Inorganic Acids ◽  
Low Activity ◽  
The Eu

AbstractThe rearing of piglets is the most difficult period in the pigs’ production because of their poorly developed digestive system and the low activity of digestive enzymes. Problems in nutrition and stress cause some disorders in the functioning of the digestive system leading to diarrhea and the mortality of piglets. Starting in 2006 in the EU, a total ban on antibiotics in their use as growth promoters was introduced. Since then, new and safe feed additives have been sought in order to replace antibiotics. Organic and inorganic acids as well as their salts were recognized as effective and safe additives. Due to their properties, they can improve feed palatability and digestibility, reduce the buffer capacity of feed, impact the development and functioning of the pig’s digestive system and improve the health and growth parameters. However, the effectiveness of acids is related to their qualitative and quantitative share in the feed additive. In this review, some strategies for using organic acids, their mixtures and also some new multi-component products will be discussed.

Effect of rhizobacteria strains on the induction of resistance in barley genotypes against Cochliobolus sativus

2020 ◽  
Vol 13 (2) ◽  
pp. 83-92 ◽  
Author(s):  
A. Adam
Keyword(s):  
Plant Growth ◽  
Pseudomonas Putida ◽  
Growth Parameters ◽  
Disease Incidence ◽  
Dry Weight ◽  
Cochliobolus Sativus ◽  
Resistance Level ◽  
Wet Weight ◽  
Number Of Leaves ◽  
Barley Genotypes

SummaryEnhancement of the resistance level in plants by rhizobacteria has been proven in several pathosystems. This study investigated the ability of four rhizobacteria strains (Pseudomonas putida BTP1 and Bacillus subtilis Bs2500, Bs2504 and Bs2508) to promote the growth in three barley genotypes and protect them against Cochliobolus sativus. Our results demonstrated that all tested rhizobacteria strains had a protective effect on barley genotypes Arabi Abiad, Banteng and WI2291. However, P. putida BTP1 and B. subtilis Bs2508 strains were the most effective as they reduced disease incidence by 53 and 38% (mean effect), respectively. On the other hand, there were significant differences among the rhizobacteria-treated genotypes on plant growth parameters, such as wet weight, dry weight, plant height and number of leaves. Pseudomonas putida BTP1 strain was the most effective as it significantly increased plant growth by 15-32%. In addition, the susceptible genotypes Arabi Abiad and WI2291 were the most responsive to rhizobacteria. This means that these genotypes have a high potential for increase of their resistance against the pathogen and enhancement of plant growth after the application of rhizobacteria. Consequently, barley seed treatment with the tested rhizobacteria could be considered as an effective biocontrol method against C. sativus.

Sign in / Sign up

Export Citation Format

Share Document