Pub Date : 2024-07-18DOI: 10.35848/1347-4065/ad6541
Tomoki Hotta, Kengo Takase, Le Duc Anh, Masaaki Tanaka
We study epitaxial growth and physical properties of heavily Fe-doped quaternary-alloy ferromagnetic semiconductor (In0.84-x ,Ga x ,Fe0.16)Sb thin films (Ga content x = 2–10%, Fe content fixed at 16%). The (In0.84-x ,Ga x ,Fe0.16)Sb films have a zinc-blende-type crystal structure without any other second phase, and all the samples exhibit intrinsic ferromagnetism with high Curie temperature (> 300 K). The carrier type of the (In0.84-x ,Ga x ,Fe0.16)Sb films is found to be changed by varying x, and a carrier-type phase diagram of (In,Ga,Fe)Sb is presented. These results suggest that (In,Ga,Fe)Sb is a promising material for semiconductor spintronic devices, such as ferromagnetic p-n junctions operating at room temperature.
我们研究了重度铁掺杂的四元合金铁磁性半导体 (In0.84-x ,Ga x ,Fe0.16)Sb 薄膜（镓含量 x = 2-10%，铁含量固定为 16%）的外延生长和物理性质。(In0.84-x,Ga x ,Fe0.16)Sb薄膜具有锌混合物型晶体结构，没有任何其他第二相，所有样品都表现出高居里温度（> 300 K）的本征铁磁性。研究发现，(In0.84-x ,Ga x ,Fe0.16)Sb 薄膜的载流子类型会随着 x 的变化而改变，并给出了(In,Ga,Fe)Sb 的载流子类型相图。这些结果表明，(In,Ga,Fe)Sb 是一种很有前途的半导体自旋电子器件材料，如在室温下工作的铁磁 p-n 结。
{"title":"Heavily Fe-doped quaternary-alloy ferromagnetic semiconductor (In,Ga,Fe)Sb","authors":"Tomoki Hotta, Kengo Takase, Le Duc Anh, Masaaki Tanaka","doi":"10.35848/1347-4065/ad6541","DOIUrl":"https://doi.org/10.35848/1347-4065/ad6541","url":null,"abstract":"\u0000 We study epitaxial growth and physical properties of heavily Fe-doped quaternary-alloy ferromagnetic semiconductor (In0.84-x\u0000 ,Ga\u0000 x\u0000 ,Fe0.16)Sb thin films (Ga content x = 2–10%, Fe content fixed at 16%). The (In0.84-x\u0000 ,Ga\u0000 x\u0000 ,Fe0.16)Sb films have a zinc-blende-type crystal structure without any other second phase, and all the samples exhibit intrinsic ferromagnetism with high Curie temperature (> 300 K). The carrier type of the (In0.84-x\u0000 ,Ga\u0000 x\u0000 ,Fe0.16)Sb films is found to be changed by varying x, and a carrier-type phase diagram of (In,Ga,Fe)Sb is presented. These results suggest that (In,Ga,Fe)Sb is a promising material for semiconductor spintronic devices, such as ferromagnetic p-n junctions operating at room temperature.","PeriodicalId":505044,"journal":{"name":"Japanese Journal of Applied Physics","volume":" 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141824669","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}
Pub Date : 2024-07-18DOI: 10.35848/1347-4065/ad6543
T. Kaizu, O. Kojima, Yasuo Minami, Takahiro Kitada, Y. Harada, T. Kita, Osamu Wada
We report lateral photoconductive properties of multilayer-stacked undoped InAs/GaAs quantum dots (QDs) for the application to photoconductive terahertz (THz) antenna devices which operate in 1.5 μm-telecom-wavelength band. The excitation power-dependent photocurrent showed a high value without saturation under high excitation power for the excitation wavelength of 1460 nm. From the reflection pump-probe signal, a fast photocarrier lifetime was derived. These results together with the low dark current characteristic support the applicability of the multilayer-stacked undoped InAs/GaAs QDs to photoconductive THz antennas operating in 1.5 μm-wavelength band.
{"title":"Lateral photoconductivity of InAs/GaAs quantum dots for 1.5 μm-wavelength excitation photoconductive terahertz antenna devices","authors":"T. Kaizu, O. Kojima, Yasuo Minami, Takahiro Kitada, Y. Harada, T. Kita, Osamu Wada","doi":"10.35848/1347-4065/ad6543","DOIUrl":"https://doi.org/10.35848/1347-4065/ad6543","url":null,"abstract":"\u0000 We report lateral photoconductive properties of multilayer-stacked undoped InAs/GaAs quantum dots (QDs) for the application to photoconductive terahertz (THz) antenna devices which operate in 1.5 μm-telecom-wavelength band. The excitation power-dependent photocurrent showed a high value without saturation under high excitation power for the excitation wavelength of 1460 nm. From the reflection pump-probe signal, a fast photocarrier lifetime was derived. These results together with the low dark current characteristic support the applicability of the multilayer-stacked undoped InAs/GaAs QDs to photoconductive THz antennas operating in 1.5 μm-wavelength band.","PeriodicalId":505044,"journal":{"name":"Japanese Journal of Applied Physics","volume":" 19","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141824125","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}
Pub Date : 2024-07-17DOI: 10.35848/1347-4065/ad6452
Y. Yamashita, Ibuki Kurita, Mario Tanaka, Yu Xiang, H. Maiwa, Leong-Chew Lim, Zhengze Xu, Sipan Liu, Xiaoning Jiang
We investigated the effectiveness of AC poling (ACP) processes for [001] direction oriented Pb(Zn1/3Nb2/3)O3-0.055PbTiO3 (PZN-PT) single crystals (SCs) and obtained dielectric constant ε33T/ε0 of 6680 and piezoelectric strain constant d33 of 2760 pC/N, piezoelectric charge constant g33 of 46.7 × 10-3Vm/N, and a figure of merit (FOM) (d33 × g33) of 129 × 10-12m2/N. These values were 19%, 31%, 10%, and 45% higher than those of DC poling PZN-PT SC, respectively. Phase change temperature Tpc, Curie temperature Tc, and acoustic impedance (Z33) of the ACP PZN-PT SC were 121 oC, 165 oC, and 30.5 MRayls, respectively. Compared with Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 SCs, the higher Tpc, Tc, FOM and lower Z33 of the PZN-PT SCs enable the applications in high temperature with better Z33 matching to water and human body, and these findings are vital for a wide range of ultrasonic transducer applications.
{"title":"Enhanced piezoelectrical properties of Pb(Zn1/3Nb2/3)O3 - PbTiO3 single crystals by AC poling","authors":"Y. Yamashita, Ibuki Kurita, Mario Tanaka, Yu Xiang, H. Maiwa, Leong-Chew Lim, Zhengze Xu, Sipan Liu, Xiaoning Jiang","doi":"10.35848/1347-4065/ad6452","DOIUrl":"https://doi.org/10.35848/1347-4065/ad6452","url":null,"abstract":"\u0000 We investigated the effectiveness of AC poling (ACP) processes for [001] direction oriented Pb(Zn1/3Nb2/3)O3-0.055PbTiO3 (PZN-PT) single crystals (SCs) and obtained dielectric constant ε33T/ε0 of 6680 and piezoelectric strain constant d33 of 2760 pC/N, piezoelectric charge constant g33 of 46.7 × 10-3Vm/N, and a figure of merit (FOM) (d33 × g33) of 129 × 10-12m2/N. These values were 19%, 31%, 10%, and 45% higher than those of DC poling PZN-PT SC, respectively. Phase change temperature Tpc, Curie temperature Tc, and acoustic impedance (Z33) of the ACP PZN-PT SC were 121 oC, 165 oC, and 30.5 MRayls, respectively. Compared with Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 SCs, the higher Tpc, Tc, FOM and lower Z33 of the PZN-PT SCs enable the applications in high temperature with better Z33 matching to water and human body, and these findings are vital for a wide range of ultrasonic transducer applications.","PeriodicalId":505044,"journal":{"name":"Japanese Journal of Applied Physics","volume":" 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141830788","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}
Pub Date : 2024-07-16DOI: 10.35848/1347-4065/ad63b1
Shun-ichiro Ohmi, Sachi Awakura, Hiroaki Imamura, Yoshito Jin
In this research, we have investigated the effect of excimer laser annealing (ELA) on the ferroelectric nondoped HfO2 (FeND-HfO2) formation deposited on Si(100) substrate. The XeCl (λ: 308 nm) ELA was irradiated as post-deposition annealing (PDA) in the N2 ambient to the 10 nm thick HfO2 deposited by RF-magnetron sputtering without substrate heating. The C-V characteristics of Al/HfO2/p-Si(100) metal/ferroelectrics/Si (MFS) diodes were gradually improved with the energy density of ELS from 170 mJ/cm2 to 270 mJ/cm2 irradiated at 200 Hz for 200 shots although charge-injection type hysteresis of 0.2-0.3 V was remained. The post-metallization annealing (PMA) at 400oC/5 min in N2/4.9%H2 ambient for Al/HfO2/p-Si(100) MFS diodes markedly improved the C-V characteristics, and negligible hysteresis with ideal flat-band voltage (VFB) was realized. The memory window (MW) of 0.42 V was achieved by the program/erase (P/E) operation with the input pulses of +3 V/100 ms and -8 V/100 ms for the MFS diode with ELA energy density of 270 mJ/cm2 at 200 Hz for 200 shots followed by the PMA..
{"title":"Influence of XeCl excimer laser annealing on the ferroelectric nondoped HfO2 formation deposited on Si(100) substrate","authors":"Shun-ichiro Ohmi, Sachi Awakura, Hiroaki Imamura, Yoshito Jin","doi":"10.35848/1347-4065/ad63b1","DOIUrl":"https://doi.org/10.35848/1347-4065/ad63b1","url":null,"abstract":"\u0000 In this research, we have investigated the effect of excimer laser annealing (ELA) on the ferroelectric nondoped HfO2 (FeND-HfO2) formation deposited on Si(100) substrate. The XeCl (λ: 308 nm) ELA was irradiated as post-deposition annealing (PDA) in the N2 ambient to the 10 nm thick HfO2 deposited by RF-magnetron sputtering without substrate heating. The C-V characteristics of Al/HfO2/p-Si(100) metal/ferroelectrics/Si (MFS) diodes were gradually improved with the energy density of ELS from 170 mJ/cm2 to 270 mJ/cm2 irradiated at 200 Hz for 200 shots although charge-injection type hysteresis of 0.2-0.3 V was remained. The post-metallization annealing (PMA) at 400oC/5 min in N2/4.9%H2 ambient for Al/HfO2/p-Si(100) MFS diodes markedly improved the C-V characteristics, and negligible hysteresis with ideal flat-band voltage (VFB) was realized. The memory window (MW) of 0.42 V was achieved by the program/erase (P/E) operation with the input pulses of +3 V/100 ms and -8 V/100 ms for the MFS diode with ELA energy density of 270 mJ/cm2 at 200 Hz for 200 shots followed by the PMA..","PeriodicalId":505044,"journal":{"name":"Japanese Journal of Applied Physics","volume":"13 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141641096","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}
Pub Date : 2024-07-12DOI: 10.35848/1347-4065/ad62cd
M. Tabaru, Cyui Wu, Kento Murata, Takahiro Aoyagi, Kentaro Nakamura
The requirement of high-quality fruits and vegetables have been increased. Sorting and grading of them in non-contact way is important, and firmness is an important criterion. In this study, we developed a non-contact measurement system for firmness of fruits and vegetables by using airborne ultrasonic wave and parabolic reflector. Focused airborne ultrasound produced vibration on the surfaces of samples and the vibrations were detected by a laser Doppler velocimeter to characterize elastic properties. First, we designed and fabricated an offset-type parabolic reflector. Then, the elastic parameters (maximum displacements, center frequencies, and damping factors) were determined based on Kelvin-Voigt model. Finally, individual differences of elastic properties of 12 kinds of samples and temporal changes in maturity state and elastic properties of three kinds of samples were observed. From the results, we confirm the developed system could be potentially used as evaluation system of firmness of fruits and vegetables.
{"title":"Non-contact measurement of firmness properties of fruits and vegetables using parabolic-reflector airborne ultrasonic transducer and laser Doppler velocimeter","authors":"M. Tabaru, Cyui Wu, Kento Murata, Takahiro Aoyagi, Kentaro Nakamura","doi":"10.35848/1347-4065/ad62cd","DOIUrl":"https://doi.org/10.35848/1347-4065/ad62cd","url":null,"abstract":"\u0000 The requirement of high-quality fruits and vegetables have been increased. Sorting and grading of them in non-contact way is important, and firmness is an important criterion. In this study, we developed a non-contact measurement system for firmness of fruits and vegetables by using airborne ultrasonic wave and parabolic reflector. Focused airborne ultrasound produced vibration on the surfaces of samples and the vibrations were detected by a laser Doppler velocimeter to characterize elastic properties. First, we designed and fabricated an offset-type parabolic reflector. Then, the elastic parameters (maximum displacements, center frequencies, and damping factors) were determined based on Kelvin-Voigt model. Finally, individual differences of elastic properties of 12 kinds of samples and temporal changes in maturity state and elastic properties of three kinds of samples were observed. From the results, we confirm the developed system could be potentially used as evaluation system of firmness of fruits and vegetables.","PeriodicalId":505044,"journal":{"name":"Japanese Journal of Applied Physics","volume":"7 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141652497","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}
Pub Date : 2024-07-12DOI: 10.35848/1347-4065/ad62ce
Masaaki Magari, Ryushi Fujimura
Dyes and pigments for coloring have issues such as fading, stability at high temperatures, and submicron coloration. To solve these issues and realize a coloring method that is easily applicable to larger areas at a lower cost, we study plasmonic coloring using dynamic wavelength tuning via photothermal deformation of self-assembled metal semi-shell nanoparticles. Using discrete dipole approximation on a nanoparticle with a photothermally deformable metal semi-shell, we construct chromaticity diagrams for various substrate materials, semi-shell materials, and nanoparticle densities as well as present the possibility of achieving a wide color gamut by plasmonic coloration.
{"title":"Numerical investigation of dynamic plasmonic color generated via photothermal deformation of a metal semi-shell structure","authors":"Masaaki Magari, Ryushi Fujimura","doi":"10.35848/1347-4065/ad62ce","DOIUrl":"https://doi.org/10.35848/1347-4065/ad62ce","url":null,"abstract":"\u0000 Dyes and pigments for coloring have issues such as fading, stability at high temperatures, and submicron coloration. To solve these issues and realize a coloring method that is easily applicable to larger areas at a lower cost, we study plasmonic coloring using dynamic wavelength tuning via photothermal deformation of self-assembled metal semi-shell nanoparticles. Using discrete dipole approximation on a nanoparticle with a photothermally deformable metal semi-shell, we construct chromaticity diagrams for various substrate materials, semi-shell materials, and nanoparticle densities as well as present the possibility of achieving a wide color gamut by plasmonic coloration.","PeriodicalId":505044,"journal":{"name":"Japanese Journal of Applied Physics","volume":"93 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141652625","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}
Pub Date : 2024-07-11DOI: 10.35848/1347-4065/ad622c
Luoke Hu, Xianbin Li, Longlong Leng, Jingui Qian, Yong Wang
Acoustofluidic manipulation of particles/cells have gained significant attention in biomedical applications. Conventional acoustofluidics based on SAWs requires accessing cleanroom facilities and expensive lithography equipment to fabricate the interdigital electrodes, limiting their popularity in applications. In this paper, we proposed a low cost and accessible PZT device combined with the glass to generate particle patterns. We have achieved diversified particle patterns including annular and honeycombed shapes either on PZT device surface or on the glass by coupling acoustic waves into the glass using the ultrasonic gel, and showed that the size and shape of particle pattern unit could be adjusted by changing the harmonics mode frequency or experimental configurations. The formation mechanisms of particle patterns were analyzed through simulation of acoustic pressure fields. Additionally, we demonstrated the harmless acoustothermal heating (below 37℃) to the activity of biological samples at the driving voltage of acoustofluidics.
{"title":"Particle patterning diversity achieved by PZT device with different experimental configurations","authors":"Luoke Hu, Xianbin Li, Longlong Leng, Jingui Qian, Yong Wang","doi":"10.35848/1347-4065/ad622c","DOIUrl":"https://doi.org/10.35848/1347-4065/ad622c","url":null,"abstract":"\u0000 Acoustofluidic manipulation of particles/cells have gained significant attention in biomedical applications. Conventional acoustofluidics based on SAWs requires accessing cleanroom facilities and expensive lithography equipment to fabricate the interdigital electrodes, limiting their popularity in applications. In this paper, we proposed a low cost and accessible PZT device combined with the glass to generate particle patterns. We have achieved diversified particle patterns including annular and honeycombed shapes either on PZT device surface or on the glass by coupling acoustic waves into the glass using the ultrasonic gel, and showed that the size and shape of particle pattern unit could be adjusted by changing the harmonics mode frequency or experimental configurations. The formation mechanisms of particle patterns were analyzed through simulation of acoustic pressure fields. Additionally, we demonstrated the harmless acoustothermal heating (below 37℃) to the activity of biological samples at the driving voltage of acoustofluidics.","PeriodicalId":505044,"journal":{"name":"Japanese Journal of Applied Physics","volume":"109 23","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141657190","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}
Pub Date : 2024-07-10DOI: 10.35848/1347-4065/ad61a7
A. Nagakubo, Tokiya Matsukura, H. Ogi
Hydrogen (H2) is an important source of next-generation energy production. The various H2 sensors developed to date cannot easily detect very low concentrations of H2 (<10 ppm) at room temperature within 100 s. In this study, we develop H2 sensors by depositing a 200-nm thick palladium (Pd) film on AT-cut quartz resonators and adding a sub-nm gold (Au) layer on the Pd surface. Moderate Au deposition on the Pd surface improves the sensitivity of the sensor by decreasing the activation energy of atomic-hydrogen migration from the surface to the subsurface. The optimal Au thickness that minimizes the activation energy is 0.5 nm. Finally, we show that the approximate detection limit at room temperature is 5 ppm.
{"title":"Sensitivity enhancement of hydrogen-gas sensor by sub-nm Au on Pd surface of a wireless quartz resonator","authors":"A. Nagakubo, Tokiya Matsukura, H. Ogi","doi":"10.35848/1347-4065/ad61a7","DOIUrl":"https://doi.org/10.35848/1347-4065/ad61a7","url":null,"abstract":"\u0000 Hydrogen (H2) is an important source of next-generation energy production. The various H2 sensors developed to date cannot easily detect very low concentrations of H2 (<10 ppm) at room temperature within 100 s. In this study, we develop H2 sensors by depositing a 200-nm thick palladium (Pd) film on AT-cut quartz resonators and adding a sub-nm gold (Au) layer on the Pd surface. Moderate Au deposition on the Pd surface improves the sensitivity of the sensor by decreasing the activation energy of atomic-hydrogen migration from the surface to the subsurface. The optimal Au thickness that minimizes the activation energy is 0.5 nm. Finally, we show that the approximate detection limit at room temperature is 5 ppm.","PeriodicalId":505044,"journal":{"name":"Japanese Journal of Applied Physics","volume":"29 22","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141662144","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}
Pub Date : 2024-07-10DOI: 10.35848/1347-4065/ad6165
Makoto Iwata, Shouma Tagata, Tomoya Koketsu, Yoshinori Takikawa, H. Miyazaki, Koji Kimura
Dielectric permittivities under dc biasing fields in the temperature range between –169 and 75°C have been investigated in (K0.95Li0.05)(Nb1–x Ta x )O3 (KLNT–x, x = 71 and 74%). Field-induced ferroelectric phase transitions in KLNT–x have been clarified in the dc field applied along the [001]c direction (in the cubic coordinate). The ferroelectric critical endpoints in KLNT–71% and KLNT–74% have been determined to be 43.5°C, 3.0 kV/cm, and 30.3°C, 2.0 kV/cm, respectively. The tricritical point at which the first-order phase transition changes to the second-order phase transition has been estimated at 10.4℃ and x = 77.4% in the temperature–concentration phase diagram. The field-induced phase transitions and dielectric tunabilities have been discussed on the basis of the Landau-type free energy density.
我们研究了 (K0.95Li0.05)(Nb1-x Ta x )O3 (KLNT-x, x = 71 和 74%)在-169 至 75°C 温度范围内直流偏压场下的介电常数。在沿 [001]c 方向（立方坐标）施加直流电场时，KLNT-x 中场诱导的铁电相变得到了澄清。KLNT-71% 和 KLNT-74% 的铁电临界点分别被确定为 43.5°C、3.0 kV/cm 和 30.3°C、2.0 kV/cm。在温度-浓度相图中，一阶相变转变为二阶相变的三临界点估计为 10.4℃，x = 77.4%。根据朗道型自由能密度讨论了场诱导的相变和介电调谐性。
{"title":"Field-induced effects and ferroelectric critical endpoint in (K0.95Li0.05)(Nb1–x\u0000 Ta\u0000 x\u0000 )O3 single crystals","authors":"Makoto Iwata, Shouma Tagata, Tomoya Koketsu, Yoshinori Takikawa, H. Miyazaki, Koji Kimura","doi":"10.35848/1347-4065/ad6165","DOIUrl":"https://doi.org/10.35848/1347-4065/ad6165","url":null,"abstract":"\u0000 Dielectric permittivities under dc biasing fields in the temperature range between –169 and 75°C have been investigated in (K0.95Li0.05)(Nb1–x\u0000 Ta\u0000 x\u0000 )O3 (KLNT–x, x = 71 and 74%). Field-induced ferroelectric phase transitions in KLNT–x have been clarified in the dc field applied along the [001]c direction (in the cubic coordinate). The ferroelectric critical endpoints in KLNT–71% and KLNT–74% have been determined to be 43.5°C, 3.0 kV/cm, and 30.3°C, 2.0 kV/cm, respectively. The tricritical point at which the first-order phase transition changes to the second-order phase transition has been estimated at 10.4℃ and x = 77.4% in the temperature–concentration phase diagram. The field-induced phase transitions and dielectric tunabilities have been discussed on the basis of the Landau-type free energy density.","PeriodicalId":505044,"journal":{"name":"Japanese Journal of Applied Physics","volume":"24 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141661940","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}
Pub Date : 2024-07-09DOI: 10.35848/1347-4065/ad60cf
Hiroki Matsuo, Tomoki Sato, Yuji Noguchi
We investigate the bulk photovoltaic (PV) effect of Cu-doped LiNbO3 single crystals with various oxidation states of Cu. The Cu-doped samples exhibit the PV response under below-bandgap excitation, and the onset of photocurrent shifts depending on partial oxygen pressures (pO2) during the annealing treatment. Open-circuit voltages (V oc) under simulated sunlight (AM 1.5G) illumination are changed by pO2, and crystals annealed at pO2 = 1.0 × 10−10 atm exhibit the highest V oc of 1,700 V. Moreover, density functional theory (DFT) calculations for Cu-doped LiNbO3 cells with Cu2+ on the Li site and the Nb site indicate that half-filled gap states derived from 3d orbitals of Cu are formed within the bandgap. Based on Glass coefficients obtained by the analyses of polarization angle-dependent photocurrent densities and the DFT calculations, we consider that Cu2+ on the Li site is the major active site for the generation and separation of electron-hole pairs under visible light at hν = 2.4 eV.
我们研究了不同铜氧化态的掺铜铌酸锂单晶体的体光伏效应。掺铜样品在低于带隙的激发下表现出光伏响应，而且光电流的起始点在退火处理过程中会随着氧分压（pO2）的变化而变化。在模拟太阳光（AM 1.5G）照射下的开路电压（V oc）随 pO2 的变化而变化，在 pO2 = 1.0 × 10-10 atm 的条件下退火的晶体显示出最高的 V oc 值 1,700 V。此外，对在锂位和铌位上掺有 Cu2+ 的 Cu 掺杂 LiNbO3 电池进行的密度泛函理论（DFT）计算表明，在带隙内形成了源于 Cu 3d 轨道的半填充隙态。根据偏振角光电流密度分析和 DFT 计算得出的格拉斯系数，我们认为在 hν = 2.4 eV 的可见光条件下，锂基上的 Cu2+ 是产生和分离电子-空穴对的主要活性位点。
{"title":"Bulk photovoltaic effect in Cu-doped LiNbO3 single crystals with controlled oxidation state","authors":"Hiroki Matsuo, Tomoki Sato, Yuji Noguchi","doi":"10.35848/1347-4065/ad60cf","DOIUrl":"https://doi.org/10.35848/1347-4065/ad60cf","url":null,"abstract":"\u0000 We investigate the bulk photovoltaic (PV) effect of Cu-doped LiNbO3 single crystals with various oxidation states of Cu. The Cu-doped samples exhibit the PV response under below-bandgap excitation, and the onset of photocurrent shifts depending on partial oxygen pressures (pO2) during the annealing treatment. Open-circuit voltages (V\u0000 oc) under simulated sunlight (AM 1.5G) illumination are changed by pO2, and crystals annealed at pO2 = 1.0 × 10−10 atm exhibit the highest V\u0000 oc of 1,700 V. Moreover, density functional theory (DFT) calculations for Cu-doped LiNbO3 cells with Cu2+ on the Li site and the Nb site indicate that half-filled gap states derived from 3d orbitals of Cu are formed within the bandgap. Based on Glass coefficients obtained by the analyses of polarization angle-dependent photocurrent densities and the DFT calculations, we consider that Cu2+ on the Li site is the major active site for the generation and separation of electron-hole pairs under visible light at hν = 2.4 eV.","PeriodicalId":505044,"journal":{"name":"Japanese Journal of Applied Physics","volume":"4 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141664022","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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