Effect Of Growth Temperature Research Articles

Effect of fine-tuned growth temperature on structural, morphological, optical, and electrical properties of Cu2O nanoparticles as candidates for supercapacitor applications

Abstract Cuprous oxide (Cu2O) nanoparticles are promising candidates for optoelectronic and energy applications due to their unique p-type semiconducting nature, optical and electrical properties. This work studies the impact of carefully controlled growth temperature on the structural and morphological, and electrical characteristics of Cu2O nanoparticles synthesized via a coprecipitation method under various temperatures (45°, 55°, 65°, and 75°C). The X-ray diffraction (XRD) analysis indicated a high crystallinity for the fabricated Cu2O nanoparticles with an average crystallite size of approximately (~29 nm), The TEM observations indicate an average particle size of approximately (~50 nm) nanometres. SEM results demonstrated a morphological transition from spherical-cubic to cubic as the aging temperature increased. The electrical properties of the prepared nanoparticles were investigated through AC conductivity and dielectric measurements were taken between 300 K and 550 K temperature range and frequencies ranged from 100 Hz to 5 MHz. Cu2O nanoparticles enhance supercapacitor performance by providing high dielectric constant at low frequencies, improving energy storage, and increasing AC conductivity for efficient charge transport. Their temperature-dependent behaviour and ability to minimize energy losses make them ideal for high-frequency and high-temperature applications. Our findings highlight the exceptional dielectric properties of Cu2O nanoparticles and their remarkable sensitivity to subtle changes in growth temperature. This fine-tuning of the growth conditions allows for the optimization of nanoparticle properties, these characteristics make them suitable candidates for supercapacitor energy applications and other emerging optoelectronic devices.

Thickness Dependence in Phase Formation and Properties of TaSe2 Layers Grown on GaP(111)B.

The effect of growth temperature and subsequent annealing on the epitaxy of both single- and few-layer TaSe2 on Se-terminated GaP(111)B substrates is investigated. The selective growth of the 1T and 1H phases is shown up to 1 ML according to X-ray and ultraviolet photoelectron spectroscopies. The 1H monolayer, favored at low temperatures, exhibits a very homogeneous coverage after annealing, while the 1T ML, grown at high temperatures, is characterized by a better in-plane orientation. Moreover, X-ray photoelectron diffraction spectroscopy performed on 1T submonolayers shows a negligible amount of mirror twins. By contrast, in multilayers, scanning transmission electron microscopy always reveals a mixture of 2Ha and 3R polytypes with very few 1T. In addition, the multilayers become Se-deficient above 500 °C, and a new interfacial phase identified as Ta1+xSe2 or TaP appears. Finally, the optimized multilayers grown between 250 and 500 °C exhibit a similar metallic behavior with a resistivity comparable to the bulk one with valuable outcomes in the formation of electrical contacts for two-dimensional (2D) material-based devices.

Effect of growth temperature on the physical properties of kesterite Cu2ZnSnS4 (CZTS) thin films

Spray pyrolysis technique was used to deposit Cu2ZnSnS4 (CZTS) thin films onto SLG substrates. The effect of substrate temperature (Tsub), ranging from 300°C to 390°C on their structure and optoelectronic properties. The structural properties reveal that all the prepared CZTS films have a kesterite structure, with a preferential orientation along (112) plane, and presence of secondary phases. XRD data indicated an improvement in crystallinity with an increase in average crystallites size, from 12.29 to 24.73 nm, while Tsub rise up to 390 °C. Raman spectra reveal CZTS formation, with two vibrational modes observed at 335 and 373 cm−1 along with a small Raman peak at 472 cm−1 associated to the Cu2S phase. Transmittance spectra show low values in the visible range with an absorption coefficient of 105 cm−2, The band gap energy (Eg) of the sprayed-CZTS films was consistently found to decrease from 1.6 to 1.38 eV as Tsub is increased from 300 to 390 °C. Hall effect measurements revealed p-type conductivity for all the samples, and the electrical conductivity increased from 1.8 to 150 (Ω.cm)−1 with substrate temperature (Tsub). Overall, experimental results demonstrate that grown CZTS thin films can be considered as a promising absorber material in solar cell devices.

Enhancement of detection performances of cadmium zinc telluride (CdZnTe) radiation detectors through sapphire substrates

Cadmium zinc telluride (CdZnTe) is a highly effective semiconductor material, renowned for its exceptional properties. In this study, we employed the close-spaced sublimation method to grow high-quality CdZnTe thick films on sapphire substrates. The effects of growth temperature on the composition, surface defects, and structural and electrical properties of CdZnTe films were examined. The investigation identified the optimal temperature conditions for the production of thick CdZnTe films of high quality. These were found to be a sublimation temperature of 675°C and a substrate temperature of 450°C. Furthermore, we have produced CdZnTe thick-film radiation detectors based on sapphire substrates. The detectors demonstrated an energy resolution of 18.9% when subjected to 59.54keV 241 Am γ-ray irradiation. The results of our investigation suggest that these CdZnTe thick film detectors have the potential to be employed in future low-cost, large-area imaging applications.

Effect of growth temperature on crystalline quality of epitaxial MnSnO3 thin films

Epitaxial single-crystal MnSnO3 thin films were deposited on single-crystal Al2O3 substrates using pulsed laser deposition (PLD) technology, and an analysis was conducted on the impact of the growth temperature on the crystalline quality of the films. The test results show that the growth of MnSnO3 thin films at 900 °C results in sharp diffraction peaks with high intensity in the c-axis direction, better crystalline quality (FWHM of XRD 2θ peak: 0.24°), less roughness (RSM: 0.67 nm) and wider optical band gap (Eg = 2.91 eV) compared with the grown samples at other temperatures. The MnSnO3 thin film deposited at 900 °C exhibits strong photoluminescence at 341.1 and 423.1 nm, as well as high ferroelectric polarization of ∼40 μC/cm2. The fabrication of epitaxial MnSnO3 thin films opens up a new avenue for further research into their ferroelectric photovoltaic properties.

Investigation of the growth temperature of AlGaAs barrier layer on optical and crystal quality of InGaAs/AlGaAs multi-quantum wells and AlGaAs single layer grown by molecular beam epitaxy (MBE)

The effect of growth temperature on the crystal quality and optical properties of InGaAs/AlGaAs multiple quantum wells (MQWs) with AlGaAs barriers was studied. The AlGaAs layers and InGaAs/AlGaAs MQWs were grown using molecular beam epitaxy (MBE). High-resolution X-ray diffraction (HRXRD) and photoluminescence (PL) were employed to assess the interface smoothness and optical properties of the materials. HRXRD analysis reveals that increasing barrier growth temperature can lead to the degradation of interface quality, as well as the decrease in the indium content and well thickness in InGaAs/AlGaAs MQWs. But the PL integral signal which is the integration of the PL spectral intensity, and represents the normalized photon number produced by the PL process increase instead. The AlGaAs single layer analysis reveals increasing temperature can increase its crystal quality and interfaces smoothness, leading to enhanced radiation recombination efficiency.

Sensitive direct converting thin film x-ray detector utilizing β-Ga2O3 fabricated via MOCVD

Ga2O3 has been considered as one of the most suitable materials for x-ray detection, but its x-ray detection performance is still at a low level due to the limitation of its quality and absorbance, especially for hard x-ray. In this work, the effects of growth temperature and miscut angle of the sapphire substrate on the crystal quality of Ga2O3 thin films were investigated based on the MOCVD technique. It was found that the crystal growth mode was transformed from island growth to step-flow growth using miscut sapphire substrates and increasing growth temperature, which was accompanied by the improvement of the crystal quality and the reduction of the density of trapped states. Ga2O3 films with optimal crystal quality were finally prepared on a 4° miscut substrate at 900 °C. The x-ray detector based on this film shows good hard x-ray response with a sensitivity of 3.72 × 105μC·Gyair−1·cm−2. Furthermore, the impacts of Ga2O3 film crystal quality and trap density on the x-ray detector were investigated in depth, and the mechanism of the photoconductive gain of the Ga2O3 thin-film x-ray detector was analyzed.

Effect of Growth Temperature on the Structural, Morphological, and Magnetic Properties of Sputtered Ni Thin Film

Effect of Growth Temperature on the Structural, Morphological, and Magnetic Properties of Sputtered Ni Thin Film

Modulating effects of temperature on CO2-inhibited isoprene emissions in Eucalyptus urophylla

Terrestrial vegetation emits substantial amounts of highly reactive isoprene, significantly impacting atmospheric chemistry and climate change. Both atmospheric carbon dioxide (CO2) concentration and temperature can influence plant isoprene emissions; however, whether these factors have a synergistic effect remains unclear, particularly for tropical/subtropical plants. In this study, we conducted in-situ controlled experiments on Eucalyptus urophylla, a representative tropical/subtropical species, to investigate the seasonal variation in the response of isoprene emissions to CO2 concentrations (ISOP-CO2 response) and to identify potential controlling factors. The results showed that high CO2 exerts a nearly linear inhibitory effect on isoprene emissions, as indicated by the slope of the ISOP-CO2 response curve. This inhibitory effect exhibited evident seasonal changes, with stronger suppression during cooler seasons and weaker suppression during warmer seasons. This finding contrasts with the default ISOP-CO2 response in the MEGAN model, which ignored seasonal variation. Further analysis showed a significant correlation between the slope of the ISOP-CO2 response curve and growth temperature from the past 10 days, indicating that these metrics are effective indicators for predicting seasonal changes. Our findings reveal a synergistic mechanism between temperature and CO2 concentration effects on isoprene emissions. By coupling the effects of growth temperature with the ISOP-CO2 response, this mechanism can be integrated into models to provide more accurate predictions of future isoprene emissions, reducing prediction biases, especially during cooler seasons.

Tailoring Ge membrane adhesion strength: Impact of growth parameters and porous layer thickness

The recent exploration of porous Germanium (PGe) techniques marks a significant advancement in the scalable production of detachable Ge membranes and devices. However, there is a notable gap in the comprehensive understanding of the critical factors necessary to control the adhesion strength of these nanomembranes. This study delves into the effects of Ge growth temperature, in-situ annealing processes, and the thickness of the PGe layer on the reorganization of the porous interlayer, subsequently influencing the properties of the separation layer. We particularly focus on how adjusting these parameters can fine-tune the adhesion strength of the epitaxial layer, ranging from a freestanding state to a fully bonded nanomembrane. A key finding is that the thermal budget experienced by the porous structure during the buffer layer's growth significantly affects the nanomembrane's adhesion characteristics; it is imperative to minimize this duration, especially at higher growth temperatures. Our research demonstrates that by precisely controlling the voids within the PGe layer, the adhesion strength can be effectively modulated through variations in the PGe layer's thickness. The outcomes of this study offer crucial insights into the controllable adhesion strength of Ge nanomembranes, paving the way for the targeted development of detachable devices.

Effect of the AlGaN Multi‐Quantum Well Growth Temperature on the Efficiency of Metal‐Organic Vapor‐Phase Epitaxy‐Grown Far‐Ultraviolet‐C Light‐Emitting Diodes Emitting near 235 nm

The effect of the active region growth temperature (TMQW) on the external quantum efficiency (EQE) of AlGaN‐based far‐ultraviolet‐C light‐emitting diodes (far‐UVC LEDs) emitting near 235 nm is investigated. AlGaN multi‐quantum well (MQW) active regions are grown at temperatures between 850 and 1100 °C by metal‐organic vapor‐phase epitaxy, while special care is taken to keep aluminum mole fractions and thicknesses constant for all MQWs. Temperature‐ and excitation‐power‐dependent photoluminescence spectroscopy reveal a more than tenfold increase of the radiative recombination efficiency (RRE) when the growth temperature increases from 850 to 1020–1060 °C. The output powers for mounted far‐UVC LEDs at 0.2 A increase from 0.5 mW for TMQW of 900 °C to 2.5 mW for TMQW of 1020 °C, corresponding to an increase in EQE from 0.04% to 0.23% at 0.2 A. However, lifetime measurements reveal a reduction of the L70 lifetime from 400 to 1 h when TMQW increases from 900 to 1060 °C. In this investigation, it is shown that optimizing the growth conditions provides a promising approach to further increase the RRE and EQE and lifetime of far‐UVC LEDs.

Correlation between photoluminescence and radiative defects in silicon oxycarbide films due to the growth temperature effect

In this work, the effect of growth temperature (678–988 °C) on silicon oxycarbide (SiCxOy) samples obtained by hot filament chemical vapor deposition (HFCVD) is reported. The samples were deposited on silicon (Si) n-type (100) and quartz substrates for optical and structural studies. At a lower temperature (678 °C), silicon oxycarbide powders were formed on Si substrates due to the homogeneous reaction occurring in the gas phase. However, for temperatures between 804 and 988 °C, silicon oxycarbide films were formed on Si substrates. By changing the temperature from 678 to 988 °C, both carbon (C) concentration (21.2–17.7 wt.%) and the relative percentage of Si–C bond density (%RtSi-C = 11.34–3.47 %) decreased, as demonstrated by EDS and FTIR measurements, respectively. On the other hand, the content of relative Si–O–Si bonds located around 1060 cm−1 remained dominant in all cases, resulting in SiCxOy films with an amorphous SiOx-type structure. These films exhibited strong photoluminescence (PL) centered in the blue region (∼3 eV), where Si–NOVS radiative centers were preferentially responsible for PL emission. At a lower temperature (678 °C), the PL intensity decreased. The determination of optical bandgap energy (Eopt) using Tauc Plots coincided with the emission due to luminescent centers (∼3 and ∼2.7 eV) observed in PL, indicating that the radiative transitions were due to defects. The AFM measurements showed an increase in roughness from 5.01 to 16.20 nm as the growth temperature decreased, as expected according to SEM measurements.

Study of the Effect of Growth Temperature on the Properties of Nitrogen-Doped Carbon Nanotubes for Designing Nanopiezotronic Devices

Study of the Effect of Growth Temperature on the Properties of Nitrogen-Doped Carbon Nanotubes for Designing Nanopiezotronic Devices

Effect of foreign impurity and growth temperatures on hexagonal structure and fundamental properties of ZnO nanorods.

This study examined the influence of growth temperature and dopant concentration on the properties of Gd- and Ni-doped zinc oxide nanorods (ZnO NRs). ZnO seed layers were deposited on glass substrates using a sol-gel and dip-coating approach. Gd- and Ni-doped ZnO NRs were hydrothermally grown on the seed layers at different temperatures such as 75, 90, and 105°C for a constant growth time of 5 h. The crystal structure, optical, surface morphology views, and electrical properties of the NRs were extensively investigated by x-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible spectroscopy, and four probe experimental methods. The XRD analysis confirmed the successful substitution of Zn2+ ions by Gd3+ and Ni2+ within the ZnO main matrices. The reordering of hexagonal structures with varied electronegativity, ionic radius dimensions, and valence electron states of Gd and Ni dopants affected seriously the fundamental characteristic features of NRs. The SEM images showed that the ZnO NRs grown at 90°C possessed a more favorable surface morphology and well-defined hexagonal shape compared with those grown at other growth temperatures. Higher dopant concentration led to an increase in NR diameter but a decrease in density depending on the increase in the space between the NRs. Additionally, the optical transmittance was found to generally enhance with increasing dopant concentration. The results obtained highlighted the interplay between growth temperature, dopant type and concentration in tailoring the structural, morphological, and optical properties of Gd- and Ni-doped ZnO NRs, paving the way for the development of optimized nanomaterials for various applications. RESEARCH HIGHLIGHTS: The XRD analysis confirmed the successful substitution of Zn2+ ions by Gd3+ and Ni2+ within the ZnO main matrices. The SEM images showed that the ZnO NRs grown at 90°C possessed a more favorable surface morphology and well-defined hexagonal shape compared with those grown at other growth temperatures. The optical transmittance was found to generally enhance with increasing dopant concentration. The results obtained highlighted the interplay between growth temperature, dopant type and concentration in tailoring the structural, morphological, and optical properties of Gd- and Ni-doped ZnO NRs, paving the way for the development of optimized nanomaterials for various applications.

Effect of growth temperature on properties of β-Ga2O3 films grown on AlN by low-pressure chemical vapor deposition

In this work, thin films of β-Ga2O3 were prepared on AlN substrates using low-pressure chemical vapor deposition (LPCVD). The effects of growth temperature on the crystal structure, surface morphology, chemical composition, and photoluminescence properties of the synthesized β-Ga2O3 thin films were then systematically investigated. The results indicated that various films grown at different temperatures in the range of 550–850 °C had a preferred growth orientation in the planar direction (−201). The surface roughness was seen to reduce gradually as the growth temperature was raised. However, excessive temperature (850 °C) led to a reduction in the densification of the prepared films. The surface chemistry of the films was analyzed using X-ray photoelectron spectroscopy (XPS) and the O/Ga ratio of the optimal film was calculated to be 1.49, which is quite close to the optimal stoichiometric ratio of 1.5. Multiple luminescence bands were obtained in the photoluminescence spectra of the films taken at room temperature, where the blue emission formed the dominant bands. The results of the study suggest that the growth temperature has a significant impact on the film properties and that appropriately increasing the growth temperature leads to substantial improvement in the overall quality of the β-Ga2O3 thin films.

Unraveling the reasons for failure to control Amaranthus albus: insights into herbicide application at different growth stages, temperature effect, and herbicide resistance on a regional scale.

This study investigates factors contributing Amaranthus albus control failure in processing tomato fields in northern Israel. The study region is characterized by a significant climate gradient from east to west, providing the opportunity to investigate the effect of critical elements of the agricultural environment, e.g., temperature. Eight populations were collected from commercial fields in this region. Post-emergence herbicide efficacy of metribuzin, a photosystem II inhibitor, and rimsulfuron, an acetolactate synthase (ALS) inhibitor, was assessed through dose-response analyses at various growth stages. Temperature effects on control efficacy and resistance mechanisms were also explored. Standard metribuzin dose (X) was ineffective on A. albus plants with more than six true-leaves, whereas 2X dose proved effective. Rimsulfuron at 16X dose was ineffective on plants with more than four true-leaves. We report here the first case of target site resistance to ALS inhibitors in A. albus, due to point mutation in the ALS gene (Pro197 to Leu). Furthermore, our findings suggest potential involvement of CYT P450 enzymes in enhanced metabolizing of rimsulfuron. An overall decrease in dry weight was observed in response to both herbicides at 16/22 °C (P < 0.0001). Rimsulfuron was effective against only one population when applied at 28/34 °C. A possible fitness cost associated with target site-resistant biotypes was observed under low temperature conditions, leading to effective control. This regional-scale study highlights the challenges faced by growers, emphasizes the need for adapting management practices to the local climatic conditions and lays the groundwork for implementing location-specific weed management strategies in commercial fields. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Effect of Growth Temperature on Strain during Growth and Crack Suppression in AlGaN Templates on Sapphire Substrates for Deep Ultraviolet Light‐Emitting Diodes

The crack formations in AlGaN templates for deep ultraviolet (DUV) light‐emitting diodes (LEDs) are investigated and successfully suppressed. The strain values in AlGaN thick layers on sapphire substrates by in situ wafer curvature measurements and ex situ X‐ray diffraction measurements are evaluated. It is found that the tensile strain during the AlGaN thick layer growth comes from a thermal expansion difference between the AlGaN thick layer and the sapphire substrate as the temperature changes from the AlN nucleation layer growth to the AlGaN thick layer growth. When the temperature change is 100 °C and less, the tensile strain of 0.1% and less is observed during the AlGaN thick layer growth, resulting in no crack formations in the AlGaN thick layer. Furthermore, a DUV LED layer structure grown on such a crack‐free AlGaN template shows no crack formations. Thus, to suppress crack formation in templates fabricated for DUV LEDs, their growth temperature must be optimized by considering thermal expansions caused by the changes in the growth temperature from the nucleation layer to the thick layer.

Effects of growth temperature on phase transformation and crystal quality of Ga2O3 films grown on Si/AlN composite substrates by MOCVD

High-quality ε-phase Ga2O3 thin film with a FWHM of 0.68° for the (002) plane in omega scan is grown on Si/AlN composite substrate by MOCVD. The crystal phase evolution and microstructure of Ga2O3 thin films at different temperatures are studied systematically. It is found that Ga2O3 changes from amorphous at 400 °C to ε-phase at 500 °C. As the temperature further rises to 600 °C, it eventually transforms into β-phase. Due to the difference of lattice mismatch, ε-Ga2O3 is crystalline with high crystallinity on the surface of the film, but amorphous at the interface, while β-Ga2O3 is polycrystalline. In addition, ε-Ga2O3 thin films not only have the smoothest surface with roughness of 2.63 nm, but also the content of point defects (such as oxygen vacancies) is significantly reduced compared with that of amorphous and β-Ga2O3 thin films. This work provides important references for the hetero-integration of Si and Ga2O3 by MOCVD, and is beneficial for the development of low cost and high crystal quality Ga2O3 thin films which are suitable for high voltage and ultraviolet optoelectronics.

Growth Temperature Effects in Nanoscale-Thick GaTe Films on c-Sapphire Substrate by Molecular Beam Epitaxy: Implications for High-Performance Optoelectronic Devices

Growth Temperature Effects in Nanoscale-Thick GaTe Films on c-Sapphire Substrate by Molecular Beam Epitaxy: Implications for High-Performance Optoelectronic Devices

The Influence Mechanism of Quantum Well Growth and Annealing Temperature on In Migration and Stress Modulation Behavior.

This study explores the effects of growth temperature of InGaN/GaN quantum well (QW) layers on indium migration, structural quality, and luminescence properties. It is found that within a specific range, the growth temperature can control the efficiency of In incorporation into QWs and strain energy accumulated in the QW structure, modulating the luminescence efficiency. Temperature-dependent photoluminescence (TDPL) measurements revealed a more pronounced localized state effect in QW samples grown at higher temperatures. Moreover, a too high annealing temperature will enhance indium migration, leading to an increased density of non-radiative recombination centers and a more pronounced quantum-confined Stark effect (QCSE), thereby reducing luminescence intensity. These findings highlight the critical role of thermal management in optimizing the performance of InGaN/GaN MQWs in LEDs and other photoelectronic devices.