InGaAsSb/AlGaAsSb multiple quantum well (MQW) structures, with their narrow band gap quaternary compositions, are well suited for devices operating in the 2–3 µm mid-infrared spectral region. In this study, to investigate the effects of compositional variation on structural properties, twenty-period MQW structures were grown by molecular beam epitaxy on (100) GaSb substrates. It was demonstrated that varying the In and As concentrations while keeping the V/III beam equivalent pressure ratio constant significantly influenced the surface morphology due to defect formation. It was found that in the samples with In concentrations ranging from 30 to 44%, low As content resulted in an increase in the number of surface defects. However, a smooth, defect-free surface and improved crystal quality were achieved at 44% In content when the As concentration in the QWs was 14% or higher. These results highlight the importance of precise compositional tuning for achieving high structural quality in mid-infrared MQW devices.
{"title":"Influence of Indium and Arsenic composition on structural properties of InGaAsSb/AlGaAsSb multi-quantum wells grown by molecular beam epitaxy","authors":"Ayşe Aygül Ergürhan , Burcu Arpapay , Sabahattin Erinç Erenoğlu , Mustafa Kulakcı , Behçet Özgür Alaydin , Didem Altun , Uğur Serincan","doi":"10.1016/j.jcrysgro.2025.128330","DOIUrl":"10.1016/j.jcrysgro.2025.128330","url":null,"abstract":"<div><div>InGaAsSb/AlGaAsSb multiple quantum well (MQW) structures, with their narrow band gap quaternary compositions, are well suited for devices operating in the 2–3 µm mid-infrared spectral region. In this study, to investigate the effects of compositional variation on structural properties, twenty-period MQW structures were grown by molecular beam epitaxy on (100) GaSb substrates. It was demonstrated that varying the In and As concentrations while keeping the V/III beam equivalent pressure ratio constant significantly influenced the surface morphology due to defect formation. It was found that in the samples with In concentrations ranging from 30 to 44%, low As content resulted in an increase in the number of surface defects. However, a smooth, defect-free surface and improved crystal quality were achieved at 44% In content when the As concentration in the QWs was 14% or higher. These results highlight the importance of precise compositional tuning for achieving high structural quality in mid-infrared MQW devices.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"670 ","pages":"Article 128330"},"PeriodicalIF":2.0,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144997669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-03DOI: 10.1016/j.jcrysgro.2025.128329
Tianbo Fan , Liqiang Jiao , Qiutong Li , Hongyu Zhao , Yihui Qu , Hongfan Guo , Xue Li , Li Li , Cong Li , Shijie Wang
It is proposed that perturbations of several tens of ppm in the deuterium content of normal water may exert measurable influences on certain physical or chemical properties during aqueous-phase processes, a phenomenon termed the “deuterium effect”. Magnesium carbonate trihydrate whiskers (MgCO3·3H2O) were synthesized by the co-precipitation method using magnesium chloride and sodium carbonate solutions prepared with water containing 40–165 ppm deuterium at 30–70 °C, and the influence of the deuterium effect on product morphology was investigated. The products were characterized using XRD and SEM. The solubility during the reaction process was determined by titration. The results indicate that changes in deuterium content lead to significant variations in crystal morphology, transforming from predominantly hexagonal prisms to mainly tetragonal prisms with inclusions of irregular hexagonal prism structures. At the same temperature, the solubility of magnesium chloride and calcium carbonate in water with different deuterium contents varies by up to 22.24 % and 17.91 %, respectively, demonstrating the significant impact of the deuterium effect on water activity and crystallization products. Theoretical calculations using the Morphology and CASTEP modules revealed that a reduction in deuterium content causes the dominant exposed facet of MgCO3·3H2O to gradually change from the (212) plane to the (301) plane, leading to a transformation of the crystals from hexagonal to tetragonal prisms. The p orbital governs the stability of surface structures, and variations in deuterium content activate the density of states of the (212) plane, resulting in morphological changes. The theoretical results are consistent with the experimental observations.
{"title":"Study on the effect of deuterium effect on the morphology of magnesium carbonate whiskers","authors":"Tianbo Fan , Liqiang Jiao , Qiutong Li , Hongyu Zhao , Yihui Qu , Hongfan Guo , Xue Li , Li Li , Cong Li , Shijie Wang","doi":"10.1016/j.jcrysgro.2025.128329","DOIUrl":"10.1016/j.jcrysgro.2025.128329","url":null,"abstract":"<div><div>It is proposed that perturbations of several tens of ppm in the deuterium content of normal water may exert measurable influences on certain physical or chemical properties during aqueous-phase processes, a phenomenon termed the “deuterium effect”. Magnesium carbonate trihydrate whiskers (MgCO<sub>3</sub>·3H<sub>2</sub>O) were synthesized by the co-precipitation method using magnesium chloride and sodium carbonate solutions prepared with water containing 40–165 ppm deuterium at 30–70 °C, and the influence of the deuterium effect on product morphology was investigated. The products were characterized using XRD and SEM. The solubility during the reaction process was determined by titration. The results indicate that changes in deuterium content lead to significant variations in crystal morphology, transforming from predominantly hexagonal prisms to mainly tetragonal prisms with inclusions of irregular hexagonal prism structures. At the same temperature, the solubility of magnesium chloride and calcium carbonate in water with different deuterium contents varies by up to 22.24 % and 17.91 %, respectively, demonstrating the significant impact of the deuterium effect on water activity and crystallization products. Theoretical calculations using the Morphology and CASTEP modules revealed that a reduction in deuterium content causes the dominant exposed facet of MgCO<sub>3</sub>·3H<sub>2</sub>O to gradually change from the (212) plane to the (301) plane, leading to a transformation of the crystals from hexagonal to tetragonal prisms. The p orbital governs the stability of surface structures, and variations in deuterium content activate the density of states of the (212) plane, resulting in morphological changes. The theoretical results are consistent with the experimental observations.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"669 ","pages":"Article 128329"},"PeriodicalIF":2.0,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144997392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-31DOI: 10.1016/j.jcrysgro.2025.128321
Ziyu Yang , Jianghai He , Chufeng Hou , Zihua Ma , Shihao Xia , Qi Liu , Qiang Wang , Yuefei Zhang , Fei Chen
The synthesis of gallium oxide (Ga2O3) thin films has predominantly utilized ozone (O3) or O2 plasma as oxygen sources. However, the impact of H2O as an oxygen precursor on the properties of Ga2O3 films has not been extensively explored. In this study, we employ thermal atomic layer deposition (T-ALD) with trimethylgallium (TMG) and water (H2O) as precursors to systematically investigate the growth characteristics of Ga2O3 films on sapphire substrates at a constant temperature of 450 °C. The H2O pulse duration is varied between 0.1 and 0.5 s. Our results reveal that the Ga2O3 films exhibit the α-phase when the H2O pulse duration ranges from 0.1 to 0.3 s. As the H2O pulse duration increases, the films undergo a transition to an amorphous structure, accompanied by the formation of significant oxygen vacancies. The maximum film roughness of 0.531 nm is observed at a pulse duration of 0.2 s, while the highest bandgap of 5.53 eV is achieved at a pulse duration of 0.3 s. Under ultraviolet illumination with a power intensity of 224 μW/cm2, the solar-blind ultraviolet detector demonstrates a photocurrent of 4.7 × 10−7 A, a dark current of 4.2 × 10−9 A, and a maximum on/off ratio of 112, with a responsivity of 0.6 mA/W. The device exhibits a response time (τr) of 0.08 s and a decay time (τd) of 5.20 s at a bias voltage of 5 V, along with persistent photoconductivity (PPC).
{"title":"Effect of pulse time control on the structural growth characteristics and optical properties of Ga2O3 thin films prepared by thermal atomic layer deposition (T-ALD)","authors":"Ziyu Yang , Jianghai He , Chufeng Hou , Zihua Ma , Shihao Xia , Qi Liu , Qiang Wang , Yuefei Zhang , Fei Chen","doi":"10.1016/j.jcrysgro.2025.128321","DOIUrl":"10.1016/j.jcrysgro.2025.128321","url":null,"abstract":"<div><div>The synthesis of gallium oxide (Ga<sub>2</sub>O<sub>3</sub>) thin films has predominantly utilized ozone (O<sub>3</sub>) or O<sub>2</sub> plasma as oxygen sources. However, the impact of H<sub>2</sub>O as an oxygen precursor on the properties of Ga<sub>2</sub>O<sub>3</sub> films has not been extensively explored. In this study, we employ thermal atomic layer deposition (T-ALD) with trimethylgallium (TMG) and water (H<sub>2</sub>O) as precursors to systematically investigate the growth characteristics of Ga<sub>2</sub>O<sub>3</sub> films on sapphire substrates at a constant temperature of 450 °C. The H<sub>2</sub>O pulse duration is varied between 0.1 and 0.5 s. Our results reveal that the Ga<sub>2</sub>O<sub>3</sub> films exhibit the α-phase when the H<sub>2</sub>O pulse duration ranges from 0.1 to 0.3 s. As the H<sub>2</sub>O pulse duration increases, the films undergo a transition to an amorphous structure, accompanied by the formation of significant oxygen vacancies. The maximum film roughness of 0.531 nm is observed at a pulse duration of 0.2 s, while the highest bandgap of 5.53 eV is achieved at a pulse duration of 0.3 s. Under ultraviolet illumination with a power intensity of 224 μW/cm<sup>2</sup>, the solar-blind ultraviolet detector demonstrates a photocurrent of 4.7 × 10<sup>−7</sup> A, a dark current of 4.2 × 10<sup>−9</sup> A, and a maximum on/off ratio of 112, with a responsivity of 0.6 mA/W. The device exhibits a response time (τ<sub>r</sub>) of 0.08 s and a decay time (τd) of 5.20 s at a bias voltage of 5 V, along with persistent photoconductivity (PPC).</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"670 ","pages":"Article 128321"},"PeriodicalIF":2.0,"publicationDate":"2025-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145005261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We have developed corundum-like Cr2O3 / α-Al2O3 heterostructures using a novel mist-CVD technique, varying the growth parameters to modify the morphology and crystallinity of the Cr2O3 films. This technique is considered as an alternative to conventional radio-frequency (RF) magnetron sputtering, which requires a subsequent annealing due to low crystal perfection of the sputtered films. Layers deposited by both techniques are analyzed. The highest crystallinity among magnetron sputtered films was achieved in case of 3-hour annealing at 350 °C, however, any of the films grown by mist-CVD possess the mosaic spread with less-misoriented blocks. Moreover, the mist-CVD films own a much more developed morphology with a substructure of specifically oriented crystallites, that can be modified directly during a growth process. It has been shown that the growth rates of Cr2O3 films by chemical vapor deposition are significantly higher than in the case of sputtering. Thereby, Cr2O3 / α-Al2O3 heterostructures grown by mist-CVD technique may have applications as functional semiconductor surfaces.
{"title":"Cr2O3 layers deposited on sapphire substrates by mist-CVD and RF magnetron sputtering","authors":"P.N. Butenko , R.B. Timashov , A.V Almaev , M.E. Boiko , A.V. Chikiryaka , L.I. Guzilova , E.S. Sergienko , M.D. Sharkov , A.I. Stepanov , V.I. Nikolaev","doi":"10.1016/j.jcrysgro.2025.128320","DOIUrl":"10.1016/j.jcrysgro.2025.128320","url":null,"abstract":"<div><div>We have developed corundum-like Cr<sub>2</sub>O<sub>3</sub> / α-Al<sub>2</sub>O<sub>3</sub> heterostructures using a novel mist-CVD technique, varying the growth parameters to modify the morphology and crystallinity of the Cr<sub>2</sub>O<sub>3</sub> films. This technique is considered as an alternative to conventional radio-frequency (RF) magnetron sputtering, which requires a subsequent annealing due to low crystal perfection of the sputtered films. Layers deposited by both techniques are analyzed. The highest crystallinity among magnetron sputtered films was achieved in case of 3-hour annealing at 350 °C, however, any of the films grown by mist-CVD possess the mosaic spread with less-misoriented blocks. Moreover, the mist-CVD films own a much more developed morphology with a substructure of specifically oriented crystallites, that can be modified directly during a growth process. It has been shown that the growth rates of Cr<sub>2</sub>O<sub>3</sub> films by chemical vapor deposition are significantly higher than in the case of sputtering. Thereby, Cr<sub>2</sub>O<sub>3</sub> / α-Al<sub>2</sub>O<sub>3</sub> heterostructures grown by mist-CVD technique may have applications as functional semiconductor surfaces.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"668 ","pages":"Article 128320"},"PeriodicalIF":2.0,"publicationDate":"2025-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144908187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-25DOI: 10.1016/j.jcrysgro.2025.128319
Quan Zhang , Junxiong Zhang , Feng Jiang , Guo Feng , Jianmin Liu , Jian Liang , Hua Li , Qing Hu
The zirconia whisker was prepared using the molten salt method with KCl/NaVO3 as the molten salt. The study focused on the effect of heat treatment on the morphology and phase of the zirconia whiskers. The results reveal that the morphology of zirconia crystals can be controlled by adjusting the process parameters of heat treatment. Specifically, when the heat treatment temperature is 950 °C, the heating rate is 3 °C/min, and the holding time is 5 h, a whisker with a length-to-diameter ratio of 100 can be produced. Excessively high or low temperatures, rapid heating rates, short holding times, and large supercooling degrees can affect the crystal growth of the molten salt. This study provides a new approach for regulating crystal growth in molten salt systems through heat treatment parameters.
{"title":"Effect of heat treatment process on the preparation of zirconia whiskers using KCl/NaVO3 molten salt","authors":"Quan Zhang , Junxiong Zhang , Feng Jiang , Guo Feng , Jianmin Liu , Jian Liang , Hua Li , Qing Hu","doi":"10.1016/j.jcrysgro.2025.128319","DOIUrl":"10.1016/j.jcrysgro.2025.128319","url":null,"abstract":"<div><div>The zirconia whisker was prepared using the molten salt method with KCl/NaVO<sub>3</sub> as the molten salt. The study focused on the effect of heat treatment on the morphology and phase of the zirconia whiskers. The results reveal that the morphology of zirconia crystals can be controlled by adjusting the process parameters of heat treatment. Specifically, when the heat treatment temperature is 950 °C, the heating rate is 3 °C/min, and the holding time is 5 h, a whisker with a length-to-diameter ratio of 100 can be produced. Excessively high or low temperatures, rapid heating rates, short holding times, and large supercooling degrees can affect the crystal growth of the molten salt. This study provides a new approach for regulating crystal growth in molten salt systems through heat treatment parameters.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"668 ","pages":"Article 128319"},"PeriodicalIF":2.0,"publicationDate":"2025-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144903095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-22DOI: 10.1016/j.jcrysgro.2025.128315
Jamal Darand , Ali Jafarian
The heat exchanger of a FC crystallizer in Zero Liquid Discharge technology suffers reduced efficiency due to the deposition of suspended particles and dissolved ions on the tube surfaces. This research utilized a compartmental modeling, encompassing nucleation, growth, dissolution, and attrition, to examine the crystallization and particulate fouling of calcium carbonate in a FC heat exchanger over time. The impact of the deposit layer developed on the inside surface of the heat exchanger tube on heat transfer and crystallizer efficiency was examined. The results indicated that supersaturation in the calcium carbonate solution triggered the primary nucleation process in the bulk flow, rendering it resistant to further supersaturation. The reduction in supersaturation after about 2000 s (from about 1 to below 0.3) leads to a minimal degree of crystallization fouling. The increased number of calcium carbonate crystal nuclei via nucleation activation, facilitates particulate deposition mechanisms. Furthermore, several relevant parameters, including circulation flow rate, operating temperature, calcium carbonate feed concentration, purge flow rate, and crystallizer efficiency were explored. The circulation flow rate and condenser temperature were determined to be the principal factors affecting particulate fouling.
{"title":"Combined crystallization-particulate fouling dynamics in a forced circulation crystallizer","authors":"Jamal Darand , Ali Jafarian","doi":"10.1016/j.jcrysgro.2025.128315","DOIUrl":"10.1016/j.jcrysgro.2025.128315","url":null,"abstract":"<div><div>The heat exchanger of a FC crystallizer in Zero Liquid Discharge technology suffers reduced efficiency due to the deposition of suspended particles and dissolved ions on the tube surfaces. This research utilized a compartmental modeling, encompassing nucleation, growth, dissolution, and attrition, to examine the crystallization and particulate fouling of calcium carbonate in a FC heat exchanger over time. The impact of the deposit layer developed on the inside surface of the heat exchanger tube on heat transfer and crystallizer efficiency was examined. The results indicated that supersaturation in the calcium carbonate solution triggered the primary nucleation process in the bulk flow, rendering it resistant to further supersaturation. The reduction in supersaturation after about 2000 s (from about 1 to below 0.3) leads to a minimal degree of crystallization fouling. The increased number of calcium carbonate crystal nuclei via nucleation activation, facilitates particulate deposition mechanisms. Furthermore, several relevant parameters, including circulation flow rate, operating temperature, calcium carbonate feed concentration, purge flow rate, and crystallizer efficiency were explored. The circulation flow rate and condenser temperature were determined to be the principal factors affecting particulate fouling.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"669 ","pages":"Article 128315"},"PeriodicalIF":2.0,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144920113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-19DOI: 10.1016/j.jcrysgro.2025.128318
Avijit Mahapatra, Malleswararao Tangi
We report a detailed study on the structural, optical, and electronic transport properties of GeTe thin films epitaxially grown on c-plane sapphire substrates via UHV molecular beam epitaxy at substrate temperatures ranging from 200 °C to 350 °C. Grazing incidence X-ray diffraction confirms single-phase rhombohedral α-GeTe across all growth temperatures, with systematic lattice expansion and improved crystallinity observed at elevated temperatures. Atomic force microscopy and X-ray reflectivity analyses reveal that surface roughness decreases significantly at intermediate growth temperatures, achieving sub-nanometre RMS values at 300 °C. Raman spectroscopy identifies a temperature-dependent redshift of A1g and A1u phonon modes, indicating strain relaxation and phonon softening, while X-ray photoelectron spectroscopy confirms minimal oxidation and near-stoichiometric Ge: Te ratios. Electrical transport measurements demonstrate degenerate p-type conductivity characterised by high hole concentrations (∼3 × 1020 cm−3) and phonon-limited carrier mobility. Films grown at 300 °C exhibit optimal structural, phononic, stoichiometric, and electronic properties, establishing it as the optimized growth temperature for high-quality α-GeTe growth. This study paves the path towards exploring the future ferroelectric properties and relevant device applications of epitaxial α-GeTe thin films.
{"title":"Substrate temperature driven optimization of epitaxial α-GeTe thin films: optical, structural, and electrical properties","authors":"Avijit Mahapatra, Malleswararao Tangi","doi":"10.1016/j.jcrysgro.2025.128318","DOIUrl":"10.1016/j.jcrysgro.2025.128318","url":null,"abstract":"<div><div>We report a detailed study on the structural, optical, and electronic transport properties of GeTe thin films epitaxially grown on c-plane sapphire substrates via UHV molecular beam epitaxy at substrate temperatures ranging from 200 °C to 350 °C. Grazing incidence X-ray diffraction confirms single-phase rhombohedral α-GeTe across all growth temperatures, with systematic lattice expansion and improved crystallinity observed at elevated temperatures. Atomic force microscopy and X-ray reflectivity analyses reveal that surface roughness decreases significantly at intermediate growth temperatures, achieving sub-nanometre RMS values at 300 °C. Raman spectroscopy identifies a temperature-dependent redshift of A<sub>1g</sub> and A<sub>1u</sub> phonon modes, indicating strain relaxation and phonon softening, while X-ray photoelectron spectroscopy confirms minimal oxidation and near-stoichiometric Ge: Te ratios. Electrical transport measurements demonstrate degenerate p-type conductivity characterised by high hole concentrations (∼3 × 10<sup>20</sup> cm<sup>−3</sup>) and phonon-limited carrier mobility. Films grown at 300 °C exhibit optimal structural, phononic, stoichiometric, and electronic properties, establishing it as the optimized growth temperature for high-quality α-GeTe growth. This study paves the path towards exploring the future ferroelectric properties and relevant device applications of epitaxial α-GeTe thin films.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"668 ","pages":"Article 128318"},"PeriodicalIF":2.0,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144890692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-12DOI: 10.1016/j.jcrysgro.2025.128316
Li Weidong , Zhang Meng , Xue Ran
Lanthanum-doped SiC nanowires (La-doped SiC NWs) were synthesized via the thermal conversion of a polycarbosilane precursor at varying pyrolysis temperatures. Polycarbosilane was employed as a provider of both the Si and C elements. Field emission tests indicated that the turn-on field of the sample decreased from 3.8 to 1.65 V/μm, with the lowest turn-on field achieved when the pyrolysis temperature was set at 900℃, and the corresponding field enhancement factor β was 5016, representing a 41.6 % increase compared to the untreated sample. Both SEM and TEM results indicated that the pyrolysis temperature significantly influenced the morphology of the nanowires. Specifically, at a pyrolysis temperature of 1000℃, the nanowires exhibited the straightest structure and the largest diameter. Additionally, the unprocessed samples had the thickest SiO2 coating layer surrounding the SiC. The results of the SAED and XRD analysis confirmed that the products maintain the cubic sphalerite structure. Findings in the present study may provide certain foundation for future studies examining the FE properties of additional one-dimensional nano-material.
{"title":"The impact of polycarbosilane pyrolysis temperature on the field emission properties of La-Doped SiC nanowires","authors":"Li Weidong , Zhang Meng , Xue Ran","doi":"10.1016/j.jcrysgro.2025.128316","DOIUrl":"10.1016/j.jcrysgro.2025.128316","url":null,"abstract":"<div><div>Lanthanum-doped SiC nanowires (La-doped SiC NWs) were synthesized via the thermal conversion of a polycarbosilane precursor at varying pyrolysis temperatures. Polycarbosilane was employed as a provider of both the Si and C elements. Field emission tests indicated that the turn-on field of the sample decreased from 3.8 to 1.65 V/μm, with the lowest turn-on field achieved when the pyrolysis temperature was set at 900℃, and the corresponding field enhancement factor β was 5016, representing a 41.6 % increase compared to the untreated sample. Both SEM and TEM results indicated that the pyrolysis temperature significantly influenced the morphology of the nanowires. Specifically, at a pyrolysis temperature of 1000℃, the nanowires exhibited the straightest structure and the largest diameter. Additionally, the unprocessed samples had the thickest SiO<sub>2</sub> coating layer surrounding the SiC. The results of the SAED and XRD analysis confirmed that the products maintain the cubic sphalerite structure. Findings in the present study may provide certain foundation for future studies examining the FE properties of additional one-dimensional nano-material.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"668 ","pages":"Article 128316"},"PeriodicalIF":2.0,"publicationDate":"2025-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144842625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cu2O crystals were grown on c-plane sapphire substrates at a high growth-temperature of approximately 960 °C using mist-chemical vapor deposition (mist-CVD), which has a potentially low environmental impact and low cost. Using X-ray diffraction analysis, Raman spectroscopy, and scanning electron microscopy, experimental results evinced the growth of Cu2O crystals. Cu2O crystals are expected to be used in low-cost luminescent materials in red region, such as light emitting diodes (LEDs) owing to their direct-bandgap energy of approximately 2.1 eV and p-type conductivity. We examined photoluminescence (PL) properties of the Cu2O crystals grown by mist-CVD. At low temperatures, we observed a clear photoluminescence peak near the band gap energy, indicating that the mist-CVD grown Cu2O crystals can be used as luminescent materials in the red region.
{"title":"Photoluminescence properties of Cu2O crystals grown by mist chemical vapor deposition on a c-plane sapphire substrate at high growth-temperature","authors":"Shuto Kobayashi , Togi Sasaki , Masaru Sakai , Tetsuya Kouno","doi":"10.1016/j.jcrysgro.2025.128317","DOIUrl":"10.1016/j.jcrysgro.2025.128317","url":null,"abstract":"<div><div>Cu<sub>2</sub>O crystals were grown on c-plane sapphire substrates at a high growth-temperature of approximately 960 °C using mist-chemical vapor deposition (mist-CVD), which has a potentially low environmental impact and low cost. Using X-ray diffraction analysis, Raman spectroscopy, and scanning electron microscopy, experimental results evinced the growth of Cu<sub>2</sub>O crystals. Cu<sub>2</sub>O crystals are expected to be used in low-cost luminescent materials in red region, such as light emitting diodes (LEDs) owing to their direct-bandgap energy of approximately 2.1 eV and p-type conductivity. We examined photoluminescence (PL) properties of the Cu<sub>2</sub>O crystals grown by mist-CVD. At low temperatures, we observed a clear photoluminescence peak near the band gap energy, indicating that the mist-CVD grown Cu<sub>2</sub>O crystals can be used as luminescent materials in the red region.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"668 ","pages":"Article 128317"},"PeriodicalIF":2.0,"publicationDate":"2025-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144863582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study provides a pioneering investigation to numerically predict the development of pore shapes, velocity, and solute concentration fields for two bubbles trapped in a solid during the horizontal-advancing solidification of, for example, a water-carbon dioxide solution. Structural porous materials can degrade microstructures, while functional porous materials improve efficiency in industries such as food, engineering, and biomedical sectors, as well as in atmospheric physics and global warming control. Using COMSOL software, the transport equations for thermal-fluid dynamics and concentration were solved to determine the pressure, velocity, temperature, and concentration fields during bubble development and coalescence. Bubbles tend to coalesce under high gravitational acceleration, low liquid thermal conductivity, and small inter-pore spacing. Concentration within and around the pores, as well as in solidified regions, increases with gravitational acceleration, ambient pressure, and surface tension. The predicted spatially dependent contact angle matches analytical results, which have been previously validated by experimental data. A systematic understanding of the mechanisms and the final shapes and concentration fields of two bubbles entrapped in the solidified region during horizontal solidification is provided
{"title":"Solute transport and coalescence of a pair of bubbles subject to horizontal solidification","authors":"Che-Lun Chiu, Pao-Te Tseng, Ming-Jie Liu, Peng-Sheng Wei","doi":"10.1016/j.jcrysgro.2025.128314","DOIUrl":"10.1016/j.jcrysgro.2025.128314","url":null,"abstract":"<div><div>This study provides a pioneering investigation to numerically predict the development of pore shapes, velocity, and solute concentration fields for two bubbles trapped in a solid during the horizontal-advancing solidification of, for example, a water-carbon dioxide solution. Structural porous materials can degrade microstructures, while functional porous materials improve efficiency in industries such as food, engineering, and biomedical sectors, as well as in atmospheric physics and global warming control. Using COMSOL software, the transport equations for thermal-fluid dynamics and concentration were solved to determine the pressure, velocity, temperature, and concentration fields during bubble development and coalescence. Bubbles tend to coalesce under high gravitational acceleration, low liquid thermal conductivity, and small inter-pore spacing. Concentration within and around the pores, as well as in solidified regions, increases with gravitational acceleration, ambient pressure, and surface tension. The predicted spatially dependent contact angle matches analytical results, which have been previously validated by experimental data. A systematic understanding of the mechanisms and the final shapes and concentration fields of two bubbles entrapped in the solidified region during horizontal solidification is provided</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"668 ","pages":"Article 128314"},"PeriodicalIF":2.0,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144770955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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