Increasing Growth Temperature Research Articles

Toughness enhancement in TiN/Zr0.37Al0.63N1.09 multilayer films

The hardness and fracture toughness of high-temperature wear-resistant transition metal aluminum nitride multilayer films depend largely on the constituting layer's structure, compositional modulation, morphology, and interface coherency. We present a study on 1-micron thick multilayered films consisting of stacked layers of TiN and Zr0.37Al0.63N1.09, each layer being 10 nm thick. The films were grown using ion-assisted reactive magnetron sputtering on MgO(001) and Si(001) at substrate temperatures ranging from ambient to 900°C. By increasing growth temperature, we found that the ZrAlN layers transition from near amorphous to nanocrystalline wurtzite to decomposed c-ZrN and w-AlN domains. Concurrently, the TiN layers exhibit strong fiber texture, polycrystallinity, and epitaxial growth carried by the ZrN domains. Both hardness and fracture stress, evaluated by nanoindentation and micromechanical tests, increase with temperature from H=24 GPaMgO, 23 GPaSi to 36 GPaMgO, 30 GPaSi, and σFSi= 6.1-7.7 GPa, respectively. An improved fracture toughness of KIC=2.4-2.8 MPa√m is related to different toughening mechanisms for the various microstructures. The difference in hardness between the substrates is related to compressive stress due to the deposition conditions and thermal contraction. The superior fracture stress is attributed to dense multilayers, free from macroscopic defects due to ion-assisted growth. After being deposited at 200°C, the multilayers remained thermally stable when vacuum annealed for 15 hours at 900°C, with no significant change in phase composition or hardness. The improved hardness, toughness, and temperature stability of the otherwise brittle nitrides are promising for industrial applications.

Influence of growth temperature on the magnetization dynamics of sputtered CoFeB thin films on various substrates and their microwave device functionality

In the present investigation, sputtering growth of 100 nm thick Co40Fe40B20 (CoFeB) film has been investigated in a low temperature range from room temperature (RT) to 400 ℃ on silicon (Si), silicon dioxide (Si/SiO2), and sapphire (Al2O3) substrates. The film surface morphology, static and dynamic magnetization were measured as a function of growth temperature and substrate. The grown films were further tested as a potential material for microwave device functionality in terms of filter and phase shifter. Surface roughness was lowest for the film grown on Si/SiO2 substrate at 200 ℃ (0.39 nm) measured from atomic force microscopy. Static magnetic properties measured by tracing magnetic hysteresis loop suggest a soft magnetic behaviour with in-plane magnetic anisotropy. Film saturation magnetization increases with the increase in growth temperature up to 200 ℃ and then decreases from 200 ℃ to 400 ℃. This suggest that the sputtering growth from room temperature to 200 ℃ offer a moderate to low interfacial stress resulting in low defects density. Gilbert damping constant (αeff) of the thin film is obtained from the ferromagnetic resonance measurements in a broad band of microwave frequencies. Damping was lowest (5.4×10−3) in the film grown at 200 ℃ on the Si/SiO2 substrate which correlates with the roughness and magnetization data. A low value of αeff is desirable for a material to be used in energy efficient spintronics and magnonic applications. The CoFeB films were also utilized in prototype microwave band-stop filter and phase shifter device applications. The filter has been tested in the frequency range from 6GHz to 25GHz with an applied magnetic bias up to 4.0 kOe. The frequency tunability with respect to the applied magnetic bias measured to be around 3.64 GHz/kOe. The maximum attenuation of −4dB was observed for the film grown on Si/SiO2 substrate at 200 ℃. Whereas, phase shifter fabricated on Si/SiO2/CoFeB film grown at 200 ℃ shows a differential phase shift up to 75°/cm. These results indicates that the CoFeB film deposited at low growth temperature can be a potential material in spintronics and CMOS applications where low temperatures are required for device fabrications.

Cationic disorder: Governing the spin-insulatronic properties of nanocrystalline ZnFe2O4 thin films

Controlling cation order/disorder in spinel offers a highly effective means of tailoring material properties by modifying inter- and intra-sub-lattice ionic interactions. In this study, we conducted high-temperature magnetization measurements (300–1000 K) to determine average Curie temperatures (TC) for nanocrystalline ZnFe2O4 thin films. Thermodynamical stability of these films under extreme conditions was investigated by assessing lattice structures, oxygen vacancies, magnetization, and electric resistivity for spin-insulatronic applications. Reversible cation inversion via heat treatments (in-situ and ex-situ) yields tunable ferrimagnetic (FiM) order in ZnFe2O4, with TC ranging from 425 to 710 K. First-principles calculations highlight effective cation inversion mitigating magnetic frustration, promoting collinear FiM ordering, and elevating TC. Oxygen vacancies further reinforce ferrimagnetism, slightly reducing resistivity through the formation of Fe-3d gap states near the Fermi level. A proposed magnetic nanophase diagram elucidates dominant competing magnetic ground states (cluster spin-glassy state, FiM, and antiferromagnetic) with increasing growth temperature, fostering innovative homo-architectures from multiple ZnFe2O4 thin films with diverse functionalities.

Optical characterization of SnS nanowires by chemical vapor deposition method: A combined experimental and DFT study

We report on synthesis of SnS nanowires grown on Si substrates by chemical vapor deposition method at various growth temperatures between 800 and 950 °C, using gold catalyst. X-ray diffraction and Raman analyses confirmed crystalline orthorhombic phase (Pbnm space group) formation. Field emission electron microscopy showed almost uniform morphology of nanowires with average diameter of 28–98 nm with variable length sizes. Diffused reflectance spectroscopy revealed an increasing bandgap with increasing growth temperature. Bandgap and optical properties of SnS were also studied using density functional theory, showing excellent agreement between experimentally and theoretically calculated bandgap values, suitable for potential optical applications.

MBE growth of SnTe films on GaAs substrates with ZnTe buffer layers

SnTe (100) single-domain thin films have been previously grown on GaAs substrates by molecular beam epitaxy but obtaining excellent crystallinity can be difficult. In this paper, ZnTe buffer layers are introduced to improve the crystallinity of SnTe films. The effects of the molecular beam flux ratio (JTe/JSn) and growth temperature (Tg) on the crystallinity are investigated to achieve high-quality layers. The surface morphology and electrical properties of the SnTe thin films are also evaluated in addition to the conventional X-ray diffraction (XRD)measurements. The crystallographic properties of the grown samples are shown to be significantly improved by introducing a ZnTe buffer layer. XRD (θ–2θ) full width at half maximum of the lowest value obtained so far is about 0.14°. It is also found that lowering JTe/JSn to 0.6 results in a reduced growth rate, and an increased growth temperature (Tg = 220 °C) promotes the migration of atoms at the growth front. Both effects contribute to improvement in the crystallographic quality, including the layer surface smoothness. The cross-sectional transmission electron microscopy observation of the sample indicates the abrupt interface formation with different lattice structures. It is also found that low growth temperatures (below 200 °C) are not favorable for the SnTe layer growth, which is confirmed by the surface morphology.

Influence of H on Sn incorporation in GeSnC alloys grown using molecular beam epitaxy

GeSnC alloys offer a route to direct bandgap semiconductors for CMOS-compatible lasers, but the use of CBr4 as a carbon source was shown to reduce Sn incorporation by 83%–92%. We report on the role of thermally cracked H in increasing Sn incorporation by 6x–9.5x, restoring up to 71% of the lost Sn, and attribute this increase to removal of Br from the growth surface as HBr prior to formation of volatile groups such as SnBr4. Furthermore, as the H flux is increased, Rutherford backscattering spectroscopy reveals a monotonic increase in both Sn and carbon incorporation. X-ray diffraction reveals tensile-strained films that are pseudomorphic with the substrate. Raman spectroscopy suggests substitutional C incorporation; both x-ray photoelectron spectroscopy and Raman suggest a lack of graphitic carbon or its other phases. For the lowest growth temperatures, scanning transmission electron microscopy reveals nanovoids that may account for the low Sn substitutional fraction in those layers. Conversely, the sample grown at high temperatures displayed abrupt interfaces, notably devoid of any voids, tin, or carbon-rich clusters. Finally, the surface roughness decreases with increasing growth temperature. These results show that atomic hydrogen provides a highly promising route to increase both Sn and C to achieve a strongly direct bandgap for optical gain and active silicon photonics.

Resilience of Emiliania huxleyi to future changes in subantarctic waters.

Lower pH and elevated temperature alter phytoplankton growth and biomass in short-term incubations, but longer-term responses and adaptation potential are less well-studied. To determine the future of the coccolithophore Emiliania huxleyi, a mixed genotype culture from subantarctic water was incubated for 720 days under present-day temperature and pH, and also projected future conditions by the year 2100. The future population exhibited a higher growth rate relative to present-day cells transferred to future conditions after 309 days, indicating adaptation or genotype selection; this was reflected by an increase in optimum growth temperature of ~2.5°C by the end of the experiment. Following transfer to opposing conditions in short-term cross-over incubations, cell volume responded rapidly, within eight generations, confirming trait plasticity. The changes in growth rate and cell volume were larger than reported in previous single stressor relationships and incubations, suggesting synergistic or additive effects of combined elevated temperature and lower pH and highlighting the importance of long-term multiple stressor experiments. At the end of the incubation there were no significant differences in cellular composition (particulate organic content and chlorophyll a), or primary production between present-day and future populations. Conversely, two independent methods showed a 50% decrease in both particulate inorganic carbon and calcification rate, consistent with the decrease in cell volume, in the future population. The observed plasticity and adaptive capacity of E. huxleyi indicate resilience to future conditions in subantarctic waters, although changes in cell volume and carbonate may alter grazing loss and cell ballast, so influencing carbon export to the deep ocean.

Performance analysis of P-SnS thin films fabricated using CBD technique for photo detector applications

In the present work, SnS thin films were prepared using the CBD technique at room temperature and varying annealing temperaturesfrom300 to 450 °C for photo detector applications. The prepared samples were characterized using different techniques for analyzing the structural, optical, morphological, and photo sensing properties of the samples. From XRD analysis, the diffraction pattern of all the prepared thin films shows the pristine SnS phase of the samples possessing an orthorhombic phase without the presence of any impurity phases. Among the fabricated thin films, the SnS thin film annealed at a temperature of 350 °C reveals the highest crystallite size. The Raman results showed the vibrational modes of SnS films and with the increase in growth temperature, the peaks are slightly shifted towards the lower wavelength region. Morphological results show that the SnS thin films exhibit a uniform morphology of 2-D petal-like morphology with different sizes. The UV-vis spectroscopic study shows the decrease in the bandgap value of the samples with the increase in annealing temperature. The photo sensing properties of the fabricated samples show the SnS sample annealed at 400 °C has a higherresponsivityvalueof6.40×10⁻²AW⁻¹,externalquantumefficiency(EQE)valueof14.9%, and the detectivity value of 6.05 × 10⁹ Jones. Finally, the transient photo response results suggest that the SnS annealed at 350 °C shows a rise and fall time of 1.5 and 2.5 s compared to the othersampleswhichwouldbebettersuitedforphotodetectorapplications. The electrical conductivity and photo-conductivity of the films increase by more than two orders with increase of film thickness from 170 nm to 915 nm. Hall Effect measurements confirm the p-type nature of the as-prepared SnS thin films.

Larger diatoms are more sensitive to temperature changes and prone to succumb to warming stress

AbstractThe effects of ocean warming on phytoplankton have been extensively studied, but little has been documented on responses of differently sized diatoms to changes of temperature over wide ranges. We grew three diatom species, Thalassiosira pseudonana, Thalassiosira weissflogii, and Thalassiosira punctigera, with cell volumes of 199, 1805, and 13,599 μm3, respectively, at seven temperatures (5, 10, 15, 20, 25, 30, and 35°C) over 15 generations, and investigated their physiological responses. The optimum growth temperature (Topt), maximum growth rates (μmax), and thermal niche width (w) decreased by 16%, 48%, and 29% per order of magnitude in cell size increment, respectively. The cell volume of each species diminished significantly and linearly with increased temperatures, by 22% in T. punctigera, 17% in T. weissflogii, and 11% in T. pseudonana, respectively. However, the cellular biogenic silica (BSi) contents increased with rising temperature till the optimum growth temperature for growth, with the sensitivity of BSi to temperature changes (Q10BSi) ranging from 1.4 in the largest to 3.4 in the smallest diatom. The largest diatom T. punctigera showed the highest deactivation energy and succumbed to warmer conditions over its Topt, while the smallest was the most tolerant of warming. Although the moderate increase in growth temperature increased the diatoms' BSi levels, warming to temperatures higher than the optimum temperature for growth significantly reduced it. Our results suggest that diatoms acclimated to warmer conditions diminish their cell size but increase their mineralization of silica, which has profound significance in ocean carbon and silica biogeochemical cyclings.

Growth of Er3+‐doped LiNbO3 thin‐film on LiTaO3 by e‐beam evaporation

AbstractGrowth of Er3+‐doped 100‐nm thick LiNbO3(LN) films on Z‐cut LiTaO3(LT) single‐crystal by e‐beam evaporation and in‐situ anneal at 600–800°C was studied. Crystalline phase, crystallographic orientation, Er3+ spectroscopic properties, constituent element valence states, defects, Er3+ concentration and stoichiometry of the films were characterized. The results show that the films are in LN single‐crystal state and orient along with c crystallographic axis. Constituent elements Li, O and Er are present in their respective single valence states Li+, O2−, Er3+, while the Nb is in two valence states Nb5+ and Nb4+. The films have Li2O‐contents around congruent point. Antisite(NbLi4+) is the major defect. Its concentration decreases, while Li2O‐content, crystallinity degree, and fluorescence intensity increase with increased growth temperature. The presence of Er3+ in the grown films is in the form of LN crystalline phase. Its concentration is considerably lower than that in initial target material because of lower e‐beam evaporation efficiency of heavy Er3+.

Growth, magnetic, transport and electronic properties of Co2TiSi Heusler alloy thin films

We have grown thin films of Co2TiSi (CTS) Heusler alloy on n-type Si (100) at different substrate temperatures by electron beam evaporator under a high vacuum. The structural, magnetic, and electric characterizations were carried out and found a strong correlation between the properties and the growth temperatures of the samples. The crystallinity and magnetic moment both were significantly improved with increasing growth temperatures from room temperature to 400 °C. The saturation magnetization of 1.85 µB at 10 K is close to the theoretical Slater–Pauling value. A large value of spin wave stiffness constant ( D = 7.2 meV- nm2) of CTS film manifests the robustness of magnetization. The temperature-dependent longitudinal resistivity demonstrated different scattering phenomenon like weak localization, electron-magnon, electron-election, and electron-phonon interactions. A decrease in residual resistivity (109–49 µΩ-cm) and an increase in residual resistivity ratio (1.2–1.39) indicate an enhancement of crystallinity and structural order of CTS films. By first principle study using DFT calculation we have analyzed the effect of atomic site disorder on electronic properties of both bulk and thin film (220) surface form of CTS Heusler alloy. It has been noticed that the ordered bulk structure shows perfect half-metallic nature but for thin film the spin polarization and moment both are deviated from identical value. The spin polarization and magnetic moment both are reduced a lot by introducing atomic site disorder in L21 ordered structure.

Effects of growth temperature and reactor pressure on AlN thin film grown by metal-organic chemical vapor deposition

Following the development of the semiconductor industry, advanced and multifunctional material aluminum nitride (AlN) is widely used. However, AlN thin film faces the dilemma of low crystal quality or cracking in practical applications. This paper presents a high crystal quality and crack-free AlN thin film with a thickness of over 510 nm grown on a sapphire substrate by metal-organic chemical vapor deposition (MOCVD). We have analyzed the thin film deposition mechanism of the MOCVD reaction system using different growth temperatures and reactor pressures and optimized the growth mode of AlN thin film. Wherein the growth temperature refers to the substrate temperature while the film is deposited. It was shown that the deposition rate of the AlN thin film is significantly affected by the reactor pressure. As shown by the x-ray diffraction patterns, the AlN thin films exhibit a (002) preferred orientation while non-(002) reflections are extremely weak. At constant pressure, the intensity of the diffraction peak of (002) orientation increased with the growth temperature. Furthermore, the surface morphology observed by atomic force microscopy revealed a decrease in the surface roughness with increasing growth temperature. The AlN thin film grown at a growth temperature of 1300 ℃ under 10,000 Pa exhibited better (002) orientation in this work. The full width at half maximum of its rocking curve was 0.033° for (002) planes. Beside, the sample showed a flat and dense surface with a root-mean-square surface roughness of 8.4 nm. This study offers an improvement in the deposition of AlN thin films, promising for AlN-based devices operated in various conditions.

Microstructural, electrical, and optoelectronic properties of BaSi2 epitaxial films grown on Si substrates by close-spaced evaporation

BaSi2, an earth-abundant photovoltaic material with a limiting efficiency of 32 %, has the interesting property that grain boundaries do not significantly degrade the film properties. In this study, we investigated the microstructure and its effect on the electrical and optoelectronic properties of the BaSi2 films grown by close-spaced evaporation. Microstructural analysis confirmed the (100)-oriented epitaxial growth on both Si(100) and Si(111) substrates. In addition to conventional epitaxial relationships, lattice matching with the BaSi2(01¯3) plane parallel to Si(110) was observed on Si(100) substrates. The density of the epitaxial domain boundary was found to decrease with increasing film thickness, increasing growth temperature, and using Si(100) substrates instead of Si(111). Hall effect measurements revealed the conductivity type transition at a temperature between 900 and 1000 ∘C and a decreasing tendency of carrier density with film thickness. There was no obvious correlation between mobility and grain boundary density, consistent with previous reports. Carrier recombination kinetics were evaluated by the microwave-detected photoconductivity decay method and the photoconductivity measurement under constant optical irradiation. Both analyses revealed weak negative correlations between excess carrier lifetime and grain boundary density, which clarified the superiority of large-grained BaSi2 films for photovoltaic applications.

EVALUATION OF ETHANOL AND BIOMASS PRODUCTION RATE BY DIFFERENT $SACCHAROMYCES~CEREVISIAE$ STRAINS DEPENDING ON EXTERNAL pH AND TEMPERATURE

Bioethanol production is in high demand due to its potential to replace transportation fuel and its ability to be renewable and long-lasting. Therefore, the bioconversion of fermentable sugars to ethanol is of central importance. The work aimed to explore yeast properties changes during fermentation at different pHs and temperature conditions. Biomass production, specific growth rate (SGR), fermentation products, and metabolite composition and quantity changes were studied at 25℃, 30℃, and 37℃ as well as pH 5 and pH 6.5 conditions. SGR data shows that at 25℃ and 30℃ pH 5 is optimal for yeast biomass production. At pH 5.0–6.5, the biomass production of the ATCC 9804 strain almost 2 times exceeds the same parameter for another strain. The highest biomass production was detected at 30℃ and pH 5. Ethanol production by yeast increases as the growth temperature decreases at pH 5 in contrast to pH 6.5, where the temperature changes within 30–37℃ range have no significant effect on it in both strains. At 30℃ ethanol concent­ra­tion in the extracellular medium reached ~117 mM in the case of ATCC 13007 strain, whereas for ATCC 9804 the same parameter was 1.4-fold lower. Both strains had the same substrate assimilation rate. Glycerol production reduces with increasing growth temperature and pH; the highest glycerol concentration (6.1 mM) was observed within 32 h growth of ATCC 9804 strain at 25℃, pH 5 and reaches 5.5 mM within 24 h growth of ATCC 13007 strain under the same conditions. At pH 5 and 6.5, the free energy for glycerol production was 2.3-fold and 4-fold higher compared to that of ethanol and acetate production processes in both strains. Gibbs free energy of ethanol production reaches the lowest value compared to the same parameter of acetate and glycerol production at pH 5, suggesting a preference for the alcoholic fermentation metabolic pathway under these conditions. The lowest acetate production was observed after 24 hours of growth of the ATCC 13007 strain at 37°C and pH 5, with ΔG = 173.9 kJ/mol. Obtained data highlights temperature stress mechanisms regulation of yeast and can be used for improving ethanol production processes and yeast genetic modification tools.

Fabrication and optical-electrical characteristics of ZnS/ZnO films by pulsed laser deposition

Zinc sulfide/Zinc oxide (ZnS/ZnO) films were prepared on silicon (Si) wafers at different temperatures via pulsed laser deposition, and the structure, morphology and optical characteristics were investigated. As the growth temperature increases, the crystallization quality of ZnS and ZnO films improves, and the surface morphology of ZnS/ZnO films becomes more uniform and dense, accompanied by grain growth. Photoluminescence spectra of ZnS/ZnO films show that there are two emission peaks located at about 380 and 500 nm. With the increase of growth temperature, the luminescence intensity of the two peaks increases first and then decreases, and the reduction of ultraviolet luminescence is more obvious, accompanied by the blueshift of the peak position. ZnS films have played a major role in the green luminescence of ZnS/ZnO films. The average transmittance of ZnS/ZnO films is about 75% in the visible light region. With the increase of growth temperature, the transmittance increases gradually, accompanied by the absorption edge moving towards the short wavelength. Current-voltage characteristics of ZnS/ZnO/Si heterojunctions show similar rectifying behavior with common p-n junction diodes. This indicates that ZnS/ZnO films have potential applications in optoelectronic devices.

Control of Al composition of mist chemical vapor deposition grown α-(AlGa)2O3 alloy thin films by acetylacetonation of Al ion

We investigated the dominant factors affecting the Al composition of α-(AlGa)2O3 alloy thin films in mist CVD, focusing on the acetylacetonation of the source solutions. The Al–acetylacetonate (acac) complex formation time was evaluated using Fourier-transform IR spectroscopy to examine the effectiveness of heating during stirring of the source solutions. Then, α-(AlGa)2O3 alloy thin films were grown in source solutions in which the state of the acac complex was changed by adding ammonia water and/or hydrochloric acid, and the Al composition increased with increasing the pH value due to the acceleration of acetylacetonation. The growth-temperature dependence of the Al composition was also experimentally investigated. The Al composition decreased with increasing growth temperature. The reasons are due to the strength of the Al–O bond or the dissociation of the Al–acac ligand.

Effects of growth temperature on structural and electrical properties of in-rich InAlN–GaN heterostructures by radio-frequency metal–organic molecular beam epitaxy

In-rich InAlN is a promising nitride semiconductor alloy for high-efficiency solar cells and wide-range light-emitting diodes due to its tunable bandgap from 0.7 to 6.2 eV. However, incomplete characterization has led to inconsistent fundamental properties in some studies. The aim of this study was to comprehensively investigate the structural, optical, and electrical properties of In-rich InAlN films grown on GaN/Al2O3 templates by RF-MOMBE at various temperatures. The methodology involved state-of-the-art metrology techniques, such as high-resolution x-ray diffraction (HRXRD), scanning electron microscopy (FE-SEM), Hall effect measurements, and transmission electron microscopy (TEM). The results showed that all InxAl1-xN films were epitaxially grown on the GaN/Al2O3 template, with the indium composition (x) decreasing with increasing growth temperature. Furthermore, phase separation of the In-rich InAlN films occurred at high growth temperatures(>550 °C), resulting in a relatively smooth surface. The optical absorption method measured the band-gap of the InxAl1-xN films, which ranged from 1.7 to 1.9 eV for x values between 0.77 and 0.91. The mobility and carrier concentrations of all In-rich InAlN films were measured at ∼60−277 cm2 V−1-s−1 and 2–7 × 1019 cm3 in the growth temperature of range 450 °C–610 °C, respectively. In conclusion, our comprehensive characterization using advanced metrology methods provides valuable insights into the properties of In-rich InAlN films, which can inform future optimization of these materials for various applications.

Increased growth temperature and vitamin B12 supplementation reduces the lag time for rapid pathogen identification in BHI agar and blood cultures.

Background: Rapid diagnostics of pathogens is essential to prescribe appropriate antibiotic therapy. The current methods for pathogen detection require the bacteria to grow in a culture medium, which is time-consuming. This increases the mortality rate and global burden of antimicrobial resistance. Culture-free detection methods are still under development and are not common in the clinical routine. Therefore, decreasing the culture time for accurately detecting infection and resistance is vital for diagnosis. Methods: This study investigated easy-to-implement factors (in a minimal laboratory set-up), including inoculum size, incubation temperature, and additional supplementation ( e.g., vitamin B12 and trace metals), that can significantly reduce the bacterial lag time (t lag). These factors were arranged in simple two-level factorial designs using Gram-positive cocci ( Staphylococcus aureus), Gram-positive bacilli ( Bacillus subtilis), and Gram-negative bacilli ( Escherichia coli and Pseudomonas aeruginosa) bacteria, including clinical isolates with known antimicrobial resistance profiles. Blood samples spiked with a clinical isolate of E. coli CCUG 17620 (Culture Collection University of Gothenburg) were also tested to see the effect of elevated incubation temperature on bacterial growth in blood cultures. Results: We observed that increased incubation temperature (42°C) along with vitamin B12 supplementation significantly reduced the t lag (10 - 115 minutes or 4% - 49%) in pure clinical isolates and blood samples spiked with E. coli CCUG17620. In the case of the blood sample, PCR results also detected bacterial DNA after only 3h of incubation and at three times the CFU/mL. Conclusion: Enrichment of bacterial culture media with growth supplements such as vitamin B12 and increased incubation temperature can be a cheap and rapid method for the early detection of pathogens. This proof-of-concept study is restricted to a few bacterial strains and growth conditions. In the future, the effect of other growth conditions and difficult-to-culture bacteria should be explored to shorten the lag phase.

The Efficiency Study of Graphene Synthesis on Copper Substrate via Chemical Vapor Deposition Method with Methanol Precursor.

Few-layer graphene was successfully synthesized on copper foil via chemical vapor deposition with methanol as a carbon source. This was confirmed by optical microscopy observation, Raman spectra measurement, I2D/IG ratio calculation, and 2D-FWHM value comparisons. Monolayer graphene was also found in similar standard procedures, but it required higher growth temperature and longer time periods. The cost-efficient growth conditions for few-layer graphene are thoroughly discussed via TEM observation and AFM measurement. In addition, it has been confirmed that the growth period can be shortened by increasing growth temperature. With the H2 gas flow rate fixed at 15 sccm, few-layer graphene was synthesized at the lower growth temperature of 700 °C in 30 min, and at 900 °C growth temperature in only 5 min. Successful growth was also achieved without adding hydrogen gas flow; this is probably because H2 can be induced from the decomposition of methanol. Through further defects study of few-layer graphene via TEM observation and AFM measurement, we tried to find possible ways for efficiency and quality management in graphene synthesis in industrial applications. Lastly, we investigated graphene formation after pre-treatment with different gas compositions, and found that gas selection is a crucial factor for a successful synthesis.

Study the optical and structural properties of SnO2 films grown by (APCVD)

In this research thin films from SnO2 semiconductor have been prepared by using (APCVD) on glass substrates. Our study focus on prepare SnO2 films with high optical quality at various temperature. The optical transmittance was measured by UV-VIS spectrophotometer. Structure properties were studied by using X-ray diffraction. (XRD) studies show that with increasing growth temperature from (350-500) 0C diffraction peaks becomes sharper indication to improve the crystallnaity, the (110) peak has strongest intensity in all films, grain size (31.5nm) was measured by using Scherrer equation .maximum transmission can be measured is (90%) at 400 0C.( AFM) where use to analyze the morphology of the tine oxides surface. Roughness and average grain size for different temperature have been investigated