Azilsartan (2-ethoxy-1-([2’-(5-oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl)-1H-benzimidazole-7-carboxylic acid) is a new angiotensin II receptor antagonist used in the treatment of hypertension. This paper describes the preparation of type I crystal and its single crystal diffraction data, the comparison of the powder diffraction data for both type I and II crystals as well as their stability and solubility in methanol.
{"title":"Crystal Type Iof Azilsartan Polymorphs: Preparation and Analysis","authors":"Yuhua Ge, Tingting Li, Jing-Song Cheng","doi":"10.4236/JCPT.2016.61001","DOIUrl":"https://doi.org/10.4236/JCPT.2016.61001","url":null,"abstract":"Azilsartan (2-ethoxy-1-([2’-(5-oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl)-1H-benzimidazole-7-carboxylic acid) is a new angiotensin II receptor antagonist used in the treatment of hypertension. This paper describes the preparation of type I crystal and its single crystal diffraction data, the comparison of the powder diffraction data for both type I and II crystals as well as their stability and solubility in methanol.","PeriodicalId":64440,"journal":{"name":"结晶过程及技术期刊(英文)","volume":"28 1","pages":"1-10"},"PeriodicalIF":0.0,"publicationDate":"2016-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70944198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Contact angle of ethylene glycol and formamide on (100) faces of NaCl, KCl, and KBr single crystal was measured, and the specific surface free energy (SSFE) was calculated. Dispersion component of the SSFE was 90.57, 93.78, and 99.52 mN·m-1 for NaCl, KCl, and KBr, respectively. Polar component of the SSFE was 1.05, 0.65, and 0.45 mN·m-1 for NaCl, KCl, and KBr. Such a large ratio of dispersion component of SSFE results from the neutrality of the crystal surface of alkali halide. Lattice component of alkali halide is 780, 717 and 689 kJ·mol-1 for NaCl, KCl, and KBr. The larger lattice enthalpy decreases dispersion component, and increases polar component of the SSFE. The larger lattice enthalpy is considered to enhance the rumpling of the crystal surface more strongly, and such rumpling is considered to decrease the neutrality of the crystal surface.
{"title":"Dispersion and Polar Component of Specific Surface Free Energy of NaCl(100), KCl(100), and KBr(100) Single Crystal Surfaces","authors":"Takaomi Suzuk, Yuya Yamada","doi":"10.4236/JCPT.2015.53006","DOIUrl":"https://doi.org/10.4236/JCPT.2015.53006","url":null,"abstract":"Contact angle of ethylene glycol and formamide on (100) faces of NaCl, KCl, and KBr single crystal was measured, and the specific surface free energy (SSFE) was calculated. Dispersion component of the SSFE was 90.57, 93.78, and 99.52 mN·m-1 for NaCl, KCl, and KBr, respectively. Polar component of the SSFE was 1.05, 0.65, and 0.45 mN·m-1 for NaCl, KCl, and KBr. Such a large ratio of dispersion component of SSFE results from the neutrality of the crystal surface of alkali halide. Lattice component of alkali halide is 780, 717 and 689 kJ·mol-1 for NaCl, KCl, and KBr. The larger lattice enthalpy decreases dispersion component, and increases polar component of the SSFE. The larger lattice enthalpy is considered to enhance the rumpling of the crystal surface more strongly, and such rumpling is considered to decrease the neutrality of the crystal surface.","PeriodicalId":64440,"journal":{"name":"结晶过程及技术期刊(英文)","volume":"5 1","pages":"43-47"},"PeriodicalIF":0.0,"publicationDate":"2015-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70943544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Slow evaporation method was used to grow pure and KCl (10 mol%) doped KAP single crystal. The solubility and metastable zone width of aqueous solutions of pure and KCl (10 mol%) doped KAP crystal were evaluated to analyze the crystallization process. Measuring the induction period τ, the critical nucleation parameters like interfacial energy (σ), energy of formation of the critical nucleus (ΔG*) were determined using the classical theory of nucleation. The structural properties and optical constants of the grown crystals have been put to test and observed that the addition of KCl results in an enhancement of properties of the crystal. Grown crystals were characterized by powder X-ray diffraction. FTIR spectra confirmed the presence of KCl in pure KAP crystal. UV- Visible spectroscopic studies revealed that addition of KCl in pure KAP crystal increased transparency from 75% to 80%. The analysis of the optical absorption data revealed the presence of both indirect and direct transitions and both of these band gaps increased with the addition of KCl. The transmittance data was analyzed to calculate the refractive index, oscillator energy, dispersion energy, electric susceptibility, zero-frequency dielectric constant and both the real and imaginary parts of the dielectric permittivity as a function of photon energy. The moments of e(E) were also determined. The dispersion i.e. spectral dependence of the refractive index was discussed according to the single-effective oscillator model proposed by Wemple and DiDomenico.
{"title":"Determination of the Metastable Zone Width, Nucleation Kinetics, Structural and Optical Properties of KCl Doped KAP Crystal","authors":"M. A. Rahman, M. Rahman","doi":"10.4236/JCPT.2015.52005","DOIUrl":"https://doi.org/10.4236/JCPT.2015.52005","url":null,"abstract":"Slow evaporation method was used to grow pure and KCl (10 mol%) doped KAP single crystal. The solubility and metastable zone width of aqueous solutions of pure and KCl (10 mol%) doped KAP crystal were evaluated to analyze the crystallization process. Measuring the induction period τ, the critical nucleation parameters like interfacial energy (σ), energy of formation of the critical nucleus (ΔG*) were determined using the classical theory of nucleation. The structural properties and optical constants of the grown crystals have been put to test and observed that the addition of KCl results in an enhancement of properties of the crystal. Grown crystals were characterized by powder X-ray diffraction. FTIR spectra confirmed the presence of KCl in pure KAP crystal. UV- Visible spectroscopic studies revealed that addition of KCl in pure KAP crystal increased transparency from 75% to 80%. The analysis of the optical absorption data revealed the presence of both indirect and direct transitions and both of these band gaps increased with the addition of KCl. The transmittance data was analyzed to calculate the refractive index, oscillator energy, dispersion energy, electric susceptibility, zero-frequency dielectric constant and both the real and imaginary parts of the dielectric permittivity as a function of photon energy. The moments of e(E) were also determined. The dispersion i.e. spectral dependence of the refractive index was discussed according to the single-effective oscillator model proposed by Wemple and DiDomenico.","PeriodicalId":64440,"journal":{"name":"结晶过程及技术期刊(英文)","volume":"5 1","pages":"31-42"},"PeriodicalIF":0.0,"publicationDate":"2015-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70943478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Poly-crystalline anatase TiO2 layer fabricated by LPCVD using titanium-tetra-iso-propoxide and NbF5 in H2-ambient was treated in conc.-HCl solution after thin layer of IIIb-group metal was deposited on the TiO2 layer. Resistivity of the as-deposited layer about 1 × 10-1 Ω·cm was drastically reduced to 3 × 10-3 Ω·cm by the wet-treatment using indium. Temperature dependence of the resistivity increased with temperature above 100 K for the wet-treated layer was quite different from that decreased above 100 K for the as-deposited layer, whereas the resistivity was saturated at lower temperatures. The resistivity at room-temperature was decreased with the thickness before the wet-treatment but independent on the thickness above 100 nm for the wet-treated layer. Indium was more effective for the resistivity reduction than gallium but aluminum was not useful for the treatment. As the results that the wet-treatment using indium was examined for the TiO2 layers deposited by various conditions, the optimum deposition condition to reduce the resistivity of the layer after the wet-treatment was clearly different from that for the as-deposited layer.
{"title":"Drastic Resistivity Reduction of CVD-TiO 2 Layers by Post-Wet-Treatment in HCl Solution","authors":"S. Yamauchi, K. Ishibashi, S. Hatakeyama","doi":"10.4236/JCPT.2015.51004","DOIUrl":"https://doi.org/10.4236/JCPT.2015.51004","url":null,"abstract":"Poly-crystalline anatase TiO2 layer fabricated by LPCVD using titanium-tetra-iso-propoxide and NbF5 in H2-ambient was treated in conc.-HCl solution after thin layer of IIIb-group metal was deposited on the TiO2 layer. Resistivity of the as-deposited layer about 1 × 10-1 Ω·cm was drastically reduced to 3 × 10-3 Ω·cm by the wet-treatment using indium. Temperature dependence of the resistivity increased with temperature above 100 K for the wet-treated layer was quite different from that decreased above 100 K for the as-deposited layer, whereas the resistivity was saturated at lower temperatures. The resistivity at room-temperature was decreased with the thickness before the wet-treatment but independent on the thickness above 100 nm for the wet-treated layer. Indium was more effective for the resistivity reduction than gallium but aluminum was not useful for the treatment. As the results that the wet-treatment using indium was examined for the TiO2 layers deposited by various conditions, the optimum deposition condition to reduce the resistivity of the layer after the wet-treatment was clearly different from that for the as-deposited layer.","PeriodicalId":64440,"journal":{"name":"结晶过程及技术期刊(英文)","volume":"12 1","pages":"24-30"},"PeriodicalIF":0.0,"publicationDate":"2015-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70943391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Low resistive TiO2 layer was deposited by low pressure chemical vapor deposition (LPCVD) at pressure around 0.25 Pa using titanium-tetra-iso-propoxide (TTIP) and NbF5 in H2-ambient. Acti-vation energy for the deposition rate on the temperature was significantly decreased to 120 kJ/mol as compared with 228 kJ/mol for the deposition in H2 without NbF5. The deposition rate linearly increased with NbF5 supply rate but gradually decreased with H2 supply rate indicated that F on the deposition surface acts as catalyst for TTIP-dissociation but is non-activated by hydrogen. Resistivity of the layer was decreased by NbF5 supply depending on the deposition temperature with the activation energy of 319 kJ/mol, whereas the energy was 244 kJ/mol for the layer deposited in H2 without NbF5. The dependence of resistivity on NbF5. and H2 supply rates suggested that the doping should be performed by sufficient NbF5 and H2 supply rate to improve the crystallinity. As a result of the optimization, the resistivity was successfully reduced to 5 × 10-2 Ω·cm. Optical transmission spectra in UV-Vis region indicated that significant absorption observed for the layer deposited in H2 was notably decreased by using NbF5. The improved optical property was better than that for the layer deposited in O2-ambient.
{"title":"Low Resistive TiO 2 Deposition by LPCVD Using TTIP and NbF 5 in Hydrogen-Ambient","authors":"S. Yamauchi, K. Ishibashi, S. Hatakeyama","doi":"10.4236/JCPT.2015.51003","DOIUrl":"https://doi.org/10.4236/JCPT.2015.51003","url":null,"abstract":"Low resistive TiO2 layer was deposited by low pressure chemical vapor deposition (LPCVD) at pressure around 0.25 Pa using titanium-tetra-iso-propoxide (TTIP) and NbF5 in H2-ambient. Acti-vation energy for the deposition rate on the temperature was significantly decreased to 120 kJ/mol as compared with 228 kJ/mol for the deposition in H2 without NbF5. The deposition rate linearly increased with NbF5 supply rate but gradually decreased with H2 supply rate indicated that F on the deposition surface acts as catalyst for TTIP-dissociation but is non-activated by hydrogen. Resistivity of the layer was decreased by NbF5 supply depending on the deposition temperature with the activation energy of 319 kJ/mol, whereas the energy was 244 kJ/mol for the layer deposited in H2 without NbF5. The dependence of resistivity on NbF5. and H2 supply rates suggested that the doping should be performed by sufficient NbF5 and H2 supply rate to improve the crystallinity. As a result of the optimization, the resistivity was successfully reduced to 5 × 10-2 Ω·cm. Optical transmission spectra in UV-Vis region indicated that significant absorption observed for the layer deposited in H2 was notably decreased by using NbF5. The improved optical property was better than that for the layer deposited in O2-ambient.","PeriodicalId":64440,"journal":{"name":"结晶过程及技术期刊(英文)","volume":"05 1","pages":"15-23"},"PeriodicalIF":0.0,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70943712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Dissolution of the (100) face of octacalcium phosphate (OCP) single crystal in weak acidic solutions (pH = 6.5; 25°C) was observed in situ using atomic force microscopy. Monomolecular steps (2.0 nm high) were observed; they originated from etch pits or crystal edges. Advancement of the dissolution process led to precipitation of nanoparticles as small as ~10 nm even though the solution was undersaturated with respect to OCP. This precipitation of nanoparticles was accompanied by a drastic decrease in the dissolution rate; however, the substrate OCP continued to dissolve, indicating that dissolution and growth occurred simultaneously on the same surface. The precipitated nanoparticles coalesced and eventually covered the entire surface without changing the surface morphology of the substrate crystal. The step height after complete coverage was ~2.0 nm, the same as that observed on the dissolving OCP surface. These findings indicate that the precipitated phase was a pseudomorph of OCP crystal.
{"title":"In Situ Atomic Force Microscopy Observation of Octacalcium Phosphate (100) Face Dissolution in Weak Acidic Solutions","authors":"K. Onuma, M. Iijima","doi":"10.4236/JCPT.2015.51001","DOIUrl":"https://doi.org/10.4236/JCPT.2015.51001","url":null,"abstract":"Dissolution of the (100) face of octacalcium phosphate (OCP) single crystal in weak acidic solutions (pH = 6.5; 25°C) was observed in situ using atomic force microscopy. Monomolecular steps (2.0 nm high) were observed; they originated from etch pits or crystal edges. Advancement of the dissolution process led to precipitation of nanoparticles as small as ~10 nm even though the solution was undersaturated with respect to OCP. This precipitation of nanoparticles was accompanied by a drastic decrease in the dissolution rate; however, the substrate OCP continued to dissolve, indicating that dissolution and growth occurred simultaneously on the same surface. The precipitated nanoparticles coalesced and eventually covered the entire surface without changing the surface morphology of the substrate crystal. The step height after complete coverage was ~2.0 nm, the same as that observed on the dissolving OCP surface. These findings indicate that the precipitated phase was a pseudomorph of OCP crystal.","PeriodicalId":64440,"journal":{"name":"结晶过程及技术期刊(英文)","volume":"05 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70943573","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We studied chemical garden in order to investigate precipitation behavior for osmotic pressure under microwave irradiation. The salt concentration and microwave irradiation power were varied. Microwave irradiation induced release of osmotic pressure and change of precipitation pattern because polar molecules vibrate and rotate in an electromagnetic field. For example, the width of precipitation increased and the number of rapture of the membrane decreased due to the release of osmotic pressure by the irradiation. Accordingly, microwave irradiation accelerated the diffusion of ionic molecules through the membrane.
{"title":"Behaviors of Crystallization for Osmotic Pressure under Microwave Irradiation","authors":"Ryosuke Nakata, Y. Asakuma","doi":"10.4236/JCPT.2015.51002","DOIUrl":"https://doi.org/10.4236/JCPT.2015.51002","url":null,"abstract":"We studied chemical garden in order to investigate precipitation behavior for osmotic pressure under microwave irradiation. The salt concentration and microwave irradiation power were varied. Microwave irradiation induced release of osmotic pressure and change of precipitation pattern because polar molecules vibrate and rotate in an electromagnetic field. For example, the width of precipitation increased and the number of rapture of the membrane decreased due to the release of osmotic pressure by the irradiation. Accordingly, microwave irradiation accelerated the diffusion of ionic molecules through the membrane.","PeriodicalId":64440,"journal":{"name":"结晶过程及技术期刊(英文)","volume":"05 1","pages":"9-14"},"PeriodicalIF":0.0,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70943649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Aono, T. Ueda, H. Abe, Shintaro Kobayashi, K. Inaba
By direct observations of transmission electron microscopy (TEM), irreversible morphological transformations of as-deposited amorphous Au/Si multilayer (a-Au/a-Si) were observed on heating. The well arrayed sequence of the multilayer changed to zigzag layered structure at 478 K (=Tzig). Finally, the zigzag structure transformed to Au nanoparticles at 508 K. The distribution of the Au nanoparticles was random within the thin film. In situ X-ray diffraction during heating can clarify partial crystallization Si (c-Si) in the multilayer at 450 K (= ), which corresponds to metal induced crystallization (MIC) from amorphous Si (a-Si) accompanying by Au diffusion. On further heating, a-Au started to crystallize at around 480 K (=Tc) and gradually grew up to 3.2 nm in radius, although the volume of c-Si was almost constant. Continuous heating caused crystal Au (c-Au) melting into liquid AuSi (l-AuSi) at 600 K (= ), which was lower than bulk eutectic temperature ( ). Due to the AuSi eutectic effect, reversible phase transition between liquid and solid occurred once temperature is larger than . Proportionally to the maximum temperatures at each cycles (673, 873 and 1073 K), both and Au crystallization temperature approaches to . Using a thermodynamic theory of the nanoparticle formation in the eutectic system, the relationship between and the nanoparticle size is explained.
通过透射电子显微镜(TEM)的直接观察，观察到在加热过程中沉积的非晶Au/Si多层膜(a-Au/a-Si)发生了不可逆的形态转变。在478 K (=Tzig)时，多层层的排列顺序变为锯齿状层状结构。最后，在508 K下，锯齿状结构转变为金纳米粒子。金纳米粒子在薄膜内的分布是随机的。加热过程中的原位x射线衍射可以在450 K(=)下澄清多层中的部分晶化Si (c-Si)，对应于非晶Si (a-Si)伴随Au扩散的金属诱导晶化(MIC)。当进一步加热时，a-Au在480 K (=Tc)左右开始结晶，半径逐渐增大到3.2 nm，而c-Si的体积几乎不变。连续加热使结晶Au (c-Au)在600 K(=)时熔化为液态AuSi (l-AuSi)，低于体共晶温度()。由于AuSi共晶效应，当温度大于时，液相与固相发生可逆相变。与每个循环的最高温度(673,873和1073 K)成比例，和Au的结晶温度接近。利用共晶体系中纳米颗粒形成的热力学理论，解释了纳米颗粒尺寸与共晶体系的关系。
{"title":"Au Nanoparticle Formation from Amorphous Au/Si Multilayer","authors":"M. Aono, T. Ueda, H. Abe, Shintaro Kobayashi, K. Inaba","doi":"10.4236/JCPT.2014.44024","DOIUrl":"https://doi.org/10.4236/JCPT.2014.44024","url":null,"abstract":"By direct observations of transmission electron microscopy (TEM), irreversible morphological transformations of as-deposited amorphous Au/Si multilayer (a-Au/a-Si) were observed on heating. The well arrayed sequence of the multilayer changed to zigzag layered structure at 478 K (=Tzig). Finally, the zigzag structure transformed to Au nanoparticles at 508 K. The distribution of the Au nanoparticles was random within the thin film. In situ X-ray diffraction during heating can clarify partial crystallization Si (c-Si) in the multilayer at 450 K (= ), which corresponds to metal induced crystallization (MIC) from amorphous Si (a-Si) accompanying by Au diffusion. On further heating, a-Au started to crystallize at around 480 K (=Tc) and gradually grew up to 3.2 nm in radius, although the volume of c-Si was almost constant. Continuous heating caused crystal Au (c-Au) melting into liquid AuSi (l-AuSi) at 600 K (= ), which was lower than bulk eutectic temperature ( ). Due to the AuSi eutectic effect, reversible phase transition between liquid and solid occurred once temperature is larger than . Proportionally to the maximum temperatures at each cycles (673, 873 and 1073 K), both and Au crystallization temperature approaches to . Using a thermodynamic theory of the nanoparticle formation in the eutectic system, the relationship between and the nanoparticle size is explained.","PeriodicalId":64440,"journal":{"name":"结晶过程及技术期刊(英文)","volume":"04 1","pages":"193-205"},"PeriodicalIF":0.0,"publicationDate":"2014-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70943662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Low pressure chemical vapor deposition (LPCVD) of anatase TiO2 as a reduction gas was demonstrated at pres- sure of 3 mtorr in comparison to that using TTIP and O2 with study for the property of the layers. Dissociation energy of TTIP in H2 was higher than that in O2 but resistivity of the layer deposited in H2 was significantly decreased to 0.2 Ω cm in contrast to the high resistivity beyond 100 Ω cm of the layer deposited in O2. UV-Vis optical transmission spectra showed absorption around 2.2 eV was increased in the layer deposited by TTIP + H2 in addition to decrease of forbidden energy gap due to increase of Urbach tail. Resistivity at low temperature below 100 K indicating the layer deposited in H2-ambient was degenerated by the high electron density but the resistivity was decreased with temperature above 100 K with the activation energy about 100 meV. A possible electronic conduction model based on kernel, grain boundary and surface trap to clarify the temperature dependent resistivity suggesting resistivity of the layer was limited by depletion region in the grain-boundary extended from the surface and the kernel with significantly low resistivity in 10-3 Ω cm order was formed in the layer.
{"title":"Low Pressure Chemical Vapor Deposition of TiO2 Layer in Hydrogen-Ambient","authors":"S. Yamauchi, K. Ishibashi, S. Hatakeyama","doi":"10.4236/JCPT.2014.44023","DOIUrl":"https://doi.org/10.4236/JCPT.2014.44023","url":null,"abstract":"Low pressure chemical vapor deposition (LPCVD) of anatase TiO2 as a reduction gas was demonstrated at pres- sure of 3 mtorr in comparison to that using TTIP and O2 with study for the property of the layers. Dissociation energy of TTIP in H2 was higher than that in O2 but resistivity of the layer deposited in H2 was significantly decreased to 0.2 Ω cm in contrast to the high resistivity beyond 100 Ω cm of the layer deposited in O2. UV-Vis optical transmission spectra showed absorption around 2.2 eV was increased in the layer deposited by TTIP + H2 in addition to decrease of forbidden energy gap due to increase of Urbach tail. Resistivity at low temperature below 100 K indicating the layer deposited in H2-ambient was degenerated by the high electron density but the resistivity was decreased with temperature above 100 K with the activation energy about 100 meV. A possible electronic conduction model based on kernel, grain boundary and surface trap to clarify the temperature dependent resistivity suggesting resistivity of the layer was limited by depletion region in the grain-boundary extended from the surface and the kernel with significantly low resistivity in 10-3 Ω cm order was formed in the layer.","PeriodicalId":64440,"journal":{"name":"结晶过程及技术期刊(英文)","volume":"04 1","pages":"185-192"},"PeriodicalIF":0.0,"publicationDate":"2014-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70943600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Takaomi Suzuki, Keiko Takahashi, M. Kawasaki, T. Kagami
Contact angles of water droplet on as-grown Z, +X, –X, and m faces of synthetic quartz crystals with growth term of 20 and 48 days, and polished Z, +X, –X, Y, and 45° cut faces of synthetic quartz crystal were observed. The average of the contact angles on as-grown Z, +X, and –X faces increased with the growth term, and they were larger than that on polished Z, +X, and –X faces. On the other hand, the average of the contact angles of water on m face decreased with the growth term, and they were smaller than that on polished Y cut face. Growth rate of the faces of synthetic crystals was measured and the order of growth rate was, m < –X < +X < Z. Specific surface free energy (SSFE) was calculated using Neumann’s equation. The SSFE of polished face was in the order of, m < –X < +X < Z, which corresponds to the order of the growth rate. The SSFE was larger for the face with larger growth rate.
{"title":"Specific Surface Free Energy of As-Grown and Polished Faces of Synthetic Quartz","authors":"Takaomi Suzuki, Keiko Takahashi, M. Kawasaki, T. Kagami","doi":"10.4236/JCPT.2014.44022","DOIUrl":"https://doi.org/10.4236/JCPT.2014.44022","url":null,"abstract":"Contact angles of water droplet on as-grown Z, +X, –X, and m faces of synthetic quartz crystals with growth term of 20 and 48 days, and polished Z, +X, –X, Y, and 45° cut faces of synthetic quartz crystal were observed. The average of the contact angles on as-grown Z, +X, and –X faces increased with the growth term, and they were larger than that on polished Z, +X, and –X faces. On the other hand, the average of the contact angles of water on m face decreased with the growth term, and they were smaller than that on polished Y cut face. Growth rate of the faces of synthetic crystals was measured and the order of growth rate was, m < –X < +X < Z. Specific surface free energy (SSFE) was calculated using Neumann’s equation. The SSFE of polished face was in the order of, m < –X < +X < Z, which corresponds to the order of the growth rate. The SSFE was larger for the face with larger growth rate.","PeriodicalId":64440,"journal":{"name":"结晶过程及技术期刊(英文)","volume":"04 1","pages":"177-184"},"PeriodicalIF":0.0,"publicationDate":"2014-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70942895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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