Self-sustained electrical oscillations (SEOs) in VO2 films have attracted considerable attention owing to their potential to emulate spiking pulses in neuromorphic circuits. However, triggering stable SEOs and the controlling oscillation frequency remain challenging because the details of circuit operation with VO2-based devices are not yet well understood. In this study, we propose a method to observe SEOs stably in a VO2-based planar device with Au/Ti facing electrodes by introducing a 50 Hz sinusoidal voltage from a curve tracer. The transient aspects, including the onset and collapse of the SEO, were captured, providing clarity on the oscillation frequency range and circuit conditions for the SEOs, which are closely correlated with the device temperature. It became clear that the parallel capacitance not only determined the oscillation frequency but also controlled the current through VO2 just after the insulator–metal transition of VO2, playing a role in triggering stable oscillations. We also successfully observed the transient aspects from in-phase to anti-phase synchronized oscillations in the coupled oscillations. This study advances the experimental procedures and applications of SEOs in VO2-based planar devices.
VO2 薄膜中的自持电振荡（SEOs）因其在神经形态电路中模拟尖峰脉冲的潜力而备受关注。然而，触发稳定的 SEOs 和控制振荡频率仍然具有挑战性，因为人们对基于 VO2 器件的电路运行细节还不甚了解。在本研究中，我们提出了一种方法，通过从曲线追踪器中引入 50 赫兹正弦电压，在基于 VO2 的平面器件中稳定观测金/钛电极的 SEOs。我们捕捉到了 SEO 的瞬态特性，包括 SEO 的起始和崩溃，从而清楚地了解了 SEO 的振荡频率范围和电路条件，这与器件温度密切相关。很明显，并联电容不仅决定了振荡频率，还控制了 VO2 在绝缘体-金属转变之后通过 VO2 的电流，在触发稳定振荡方面发挥了作用。我们还成功观测到了耦合振荡中从同相同步振荡到反相同步振荡的瞬态。这项研究推进了基于 VO2 的平面器件中 SEOs 的实验程序和应用。
{"title":"Observation of transient aspects of self-sustained oscillations and the role of parallel capacitance in VO2-based planar devices","authors":"Junpei Kidokoro, Md. Suruz Mian, Lamisa Hoque, Peng Yu, K. Okimura, Toshihiro Nakanishi","doi":"10.1063/5.0211327","DOIUrl":"https://doi.org/10.1063/5.0211327","url":null,"abstract":"Self-sustained electrical oscillations (SEOs) in VO2 films have attracted considerable attention owing to their potential to emulate spiking pulses in neuromorphic circuits. However, triggering stable SEOs and the controlling oscillation frequency remain challenging because the details of circuit operation with VO2-based devices are not yet well understood. In this study, we propose a method to observe SEOs stably in a VO2-based planar device with Au/Ti facing electrodes by introducing a 50 Hz sinusoidal voltage from a curve tracer. The transient aspects, including the onset and collapse of the SEO, were captured, providing clarity on the oscillation frequency range and circuit conditions for the SEOs, which are closely correlated with the device temperature. It became clear that the parallel capacitance not only determined the oscillation frequency but also controlled the current through VO2 just after the insulator–metal transition of VO2, playing a role in triggering stable oscillations. We also successfully observed the transient aspects from in-phase to anti-phase synchronized oscillations in the coupled oscillations. This study advances the experimental procedures and applications of SEOs in VO2-based planar devices.","PeriodicalId":502933,"journal":{"name":"Journal of Applied Physics","volume":"48 22","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141923699","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}
A. Datta, H. Mei, A. Lebedinsky, P. Halasyamani, S. Motakef
We report on the development of the first-ever inorganic radiation-hard moisture-insensitive large volume spectroscopic semiconductor-based scintillator with less than 2 ns decay time and light yields as high as 8000 ph/MeV. Despite extensive research into scintillator materials, the quest for an ideal scintillator combining ultrafast decay times (akin to BaF2 and Yb-doped scintillators such as Lu2O3:Yb), high light yields (exceeding 2000 photons per MeV), spectroscopic capabilities, and exceptional radiation hardness remain unfulfilled. In this study, we demonstrate and report for the first time the viability of large-volume (up to 20 mm thickness) gallium oxide (β-Ga2O3) semiconductor-based scintillators for applications requiring these properties. These β-Ga2O3 scintillators were grown using the fast turnaround (∼2 days) crucible-free optical float zone (FZ) technique. The high light yield and ultrafast decay time of these high-purity n-type semiconductors with free carrier concentration of 6 × 1017 cm−3 are attributed to native defects, specifically oxygen vacancies (VO) and gallium–oxygen vacancy pairs (VGa–VO), generated during optimized FZ growth. The ultrafast decay, along with high light yield, enables excellent timing resolution and high count rate detection for applications like time-of-flight positron emission tomography, physics experiments, and nuclear safety. The radiation hardness of these devices has been documented in a separate publication.
{"title":"Gallium oxide semiconductor-based large volume ultrafast radiation hard spectroscopic scintillators","authors":"A. Datta, H. Mei, A. Lebedinsky, P. Halasyamani, S. Motakef","doi":"10.1063/5.0219987","DOIUrl":"https://doi.org/10.1063/5.0219987","url":null,"abstract":"We report on the development of the first-ever inorganic radiation-hard moisture-insensitive large volume spectroscopic semiconductor-based scintillator with less than 2 ns decay time and light yields as high as 8000 ph/MeV. Despite extensive research into scintillator materials, the quest for an ideal scintillator combining ultrafast decay times (akin to BaF2 and Yb-doped scintillators such as Lu2O3:Yb), high light yields (exceeding 2000 photons per MeV), spectroscopic capabilities, and exceptional radiation hardness remain unfulfilled. In this study, we demonstrate and report for the first time the viability of large-volume (up to 20 mm thickness) gallium oxide (β-Ga2O3) semiconductor-based scintillators for applications requiring these properties. These β-Ga2O3 scintillators were grown using the fast turnaround (∼2 days) crucible-free optical float zone (FZ) technique. The high light yield and ultrafast decay time of these high-purity n-type semiconductors with free carrier concentration of 6 × 1017 cm−3 are attributed to native defects, specifically oxygen vacancies (VO) and gallium–oxygen vacancy pairs (VGa–VO), generated during optimized FZ growth. The ultrafast decay, along with high light yield, enables excellent timing resolution and high count rate detection for applications like time-of-flight positron emission tomography, physics experiments, and nuclear safety. The radiation hardness of these devices has been documented in a separate publication.","PeriodicalId":502933,"journal":{"name":"Journal of Applied Physics","volume":"59 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141922768","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}
J. Orlianges, O. Allegret, E. Sirjita, A. Masson, A. Boulle, V. Théry, S. Tardif, J. S. Micha, A. Crunteanu
We demonstrate the integration of vanadium dioxide single-crystal nanobeams fabricated by modified vapor–liquid–solid method as electrical switching elements into a radio-frequency transmission line and evaluate the performances of the overall device in modulating the transmission of the conveyed RF electromagnetic waves. The switching capability of the RF device is based on the metal–insulator transition of VO2 nanobeams, with an on/off electrical switching ratio of 104, i.e., resistance modulation from more than 106Ω when the wires are in the insulating state to only ≈20Ω when they are in the metal-like state. The thermal and electrical activation of the VO2 wires between the two dissimilar states is resulting in RF switching performances characterized by more than 15 dB change in the transmission coefficient of the device over the 100 MHz–24 GHz frequency domain.
{"title":"Electrical activation of insulator-to-metal transition in vanadium dioxide single-crystal nanobeam and their high-frequency switching performances","authors":"J. Orlianges, O. Allegret, E. Sirjita, A. Masson, A. Boulle, V. Théry, S. Tardif, J. S. Micha, A. Crunteanu","doi":"10.1063/5.0221152","DOIUrl":"https://doi.org/10.1063/5.0221152","url":null,"abstract":"We demonstrate the integration of vanadium dioxide single-crystal nanobeams fabricated by modified vapor–liquid–solid method as electrical switching elements into a radio-frequency transmission line and evaluate the performances of the overall device in modulating the transmission of the conveyed RF electromagnetic waves. The switching capability of the RF device is based on the metal–insulator transition of VO2 nanobeams, with an on/off electrical switching ratio of 104, i.e., resistance modulation from more than 106Ω when the wires are in the insulating state to only ≈20Ω when they are in the metal-like state. The thermal and electrical activation of the VO2 wires between the two dissimilar states is resulting in RF switching performances characterized by more than 15 dB change in the transmission coefficient of the device over the 100 MHz–24 GHz frequency domain.","PeriodicalId":502933,"journal":{"name":"Journal of Applied Physics","volume":"15 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141925101","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}
Kitaev chain is one of the important physical models for studying topological quantum states and quantum computing. We here propose an approach to simulate the one-dimensional Kitaev chain via a circuit of superconducting qubits. In our approach, all coupling parameters can be controlled independently, and a nontrivial gauge phase is constructed. We also study the environmental effects on the topological states of the Kitaev chain. In addition to the independent environment surrounding each qubit, we consider the common environment shared by neighboring qubits. Such an environment can generate effective non-Hermitian dissipative coupling between qubits. Through analysis and numerical calculation, we demonstrate that the common environment can significantly affect the topological properties of the qubit chain. Moreover, we observe that dissipative couplings at the edges of the Kitaev chain affect the topological states more strongly than those located elsewhere. Our work may provide a new way to explore topological phase transitions and environmental effects on topological physics using superconducting qubit circuits.
{"title":"Simulation of Kitaev chain using one-dimensional chain of superconducting qubits and environmental effects on topological states","authors":"Yang Zhang, Yun-Qiu Ge, Yu-xi Liu","doi":"10.1063/5.0224271","DOIUrl":"https://doi.org/10.1063/5.0224271","url":null,"abstract":"Kitaev chain is one of the important physical models for studying topological quantum states and quantum computing. We here propose an approach to simulate the one-dimensional Kitaev chain via a circuit of superconducting qubits. In our approach, all coupling parameters can be controlled independently, and a nontrivial gauge phase is constructed. We also study the environmental effects on the topological states of the Kitaev chain. In addition to the independent environment surrounding each qubit, we consider the common environment shared by neighboring qubits. Such an environment can generate effective non-Hermitian dissipative coupling between qubits. Through analysis and numerical calculation, we demonstrate that the common environment can significantly affect the topological properties of the qubit chain. Moreover, we observe that dissipative couplings at the edges of the Kitaev chain affect the topological states more strongly than those located elsewhere. Our work may provide a new way to explore topological phase transitions and environmental effects on topological physics using superconducting qubit circuits.","PeriodicalId":502933,"journal":{"name":"Journal of Applied Physics","volume":"23 14","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141925031","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}
The absorption and photoluminescence (PL) spectra of negatively photodoped ZnO nanocrystals dispersed in ethanol are measured under a stepwise photodoping process at room temperature. The spectra are measured almost simultaneously at each photodoping level and compared in detail to discuss the origin of the spectral change. The redshift of the PL spectrum and the increase of its intensity are clearly observed in the early stage of photodoping and are attributed to the trion luminescence. The PL spectrum is found to split into two peaks for highly photodoped nanocrystals. The cause of the splitting is discussed in terms of its dependence on the nanocrystal size.
{"title":"Optical properties of ZnO nanocrystals under photo-induced electron doping","authors":"Sekika Yamamoto, Tenta Ushida","doi":"10.1063/5.0219897","DOIUrl":"https://doi.org/10.1063/5.0219897","url":null,"abstract":"The absorption and photoluminescence (PL) spectra of negatively photodoped ZnO nanocrystals dispersed in ethanol are measured under a stepwise photodoping process at room temperature. The spectra are measured almost simultaneously at each photodoping level and compared in detail to discuss the origin of the spectral change. The redshift of the PL spectrum and the increase of its intensity are clearly observed in the early stage of photodoping and are attributed to the trion luminescence. The PL spectrum is found to split into two peaks for highly photodoped nanocrystals. The cause of the splitting is discussed in terms of its dependence on the nanocrystal size.","PeriodicalId":502933,"journal":{"name":"Journal of Applied Physics","volume":"15 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141923299","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}
Photo modulated optical reflectance (PMOR) is an ideal ultra-shallow junction area metrology technique for measurement of transistor dopant distribution in integrated circuit fabrication, and the characterization of process parameters such as implant energy, implant angle, and implant dose has a significant impact on the accuracy of the ion implantation process. This study utilized deep learning to analyze various process parameters concurrently and assessed its performance on boron-doped silicon samples, the data were obtained from the power curves measured from Carrier Illumination (CI) experiments in PMOR, a deep learning model with multi-task learning architecture was developed and trained to characterize multiple process parameters, and the PMOR model incorporating a multi-task learning architecture for process parameters demonstrated superior performance in terms of accuracy and speed of characterization. The analyses indicated that applying deep learning methods to CI metrology in PMOR technology is feasible. In particular, compared with the conventional carrier irradiation technique, the ability to obtain the implantation dose and doping profile along with other process parameters such as implantation energy, implantation angle, and implantation type can better assist in the accurate realization of the ion implantation process with acceptable accuracy and time cost.
光调制光学反射（PMOR）是测量集成电路制造中晶体管掺杂分布的一种理想的超浅结面积计量技术，而植入能量、植入角度和植入剂量等工艺参数的表征对离子注入工艺的准确性有重要影响。本研究利用深度学习并发分析各种工艺参数，并评估了其在掺硼硅样品上的性能，数据来自 PMOR 中载流子照明（CI）实验测量的功率曲线，开发并训练了具有多任务学习架构的深度学习模型，以表征多个工艺参数，针对工艺参数采用多任务学习架构的 PMOR 模型在表征的准确性和速度方面都表现出卓越的性能。分析表明，将深度学习方法应用于 PMOR 技术中的 CI 计量是可行的。特别是，与传统的载流子辐照技术相比，在获得植入剂量和掺杂曲线的同时，还能获得植入能量、植入角度和植入类型等其他工艺参数，更有助于以可接受的精度和时间成本准确实现离子注入工艺。
{"title":"Deep learning-based characterization of ion implantation parameters for photo modulated optical reflectance","authors":"Xuesong Wang, Lijun Zhang, Yong Sun, Jing Min, Zhongyu Wang, Shiyuan Liu, Xiuguo Chen, Zirong Tang","doi":"10.1063/5.0210816","DOIUrl":"https://doi.org/10.1063/5.0210816","url":null,"abstract":"Photo modulated optical reflectance (PMOR) is an ideal ultra-shallow junction area metrology technique for measurement of transistor dopant distribution in integrated circuit fabrication, and the characterization of process parameters such as implant energy, implant angle, and implant dose has a significant impact on the accuracy of the ion implantation process. This study utilized deep learning to analyze various process parameters concurrently and assessed its performance on boron-doped silicon samples, the data were obtained from the power curves measured from Carrier Illumination (CI) experiments in PMOR, a deep learning model with multi-task learning architecture was developed and trained to characterize multiple process parameters, and the PMOR model incorporating a multi-task learning architecture for process parameters demonstrated superior performance in terms of accuracy and speed of characterization. The analyses indicated that applying deep learning methods to CI metrology in PMOR technology is feasible. In particular, compared with the conventional carrier irradiation technique, the ability to obtain the implantation dose and doping profile along with other process parameters such as implantation energy, implantation angle, and implantation type can better assist in the accurate realization of the ion implantation process with acceptable accuracy and time cost.","PeriodicalId":502933,"journal":{"name":"Journal of Applied Physics","volume":"11 19","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141925207","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}
This study investigates the impact of biaxial strain on monolayer black phosphorus (BP) through first-principles calculations, confirming its stability and subsequently modifying its photocatalytic performance. Under biaxial strain, BP exhibits a direct bandgap suitable for photocatalytic hydrogen production during water splitting, albeit with limitations due to its valence band maximum edge. A distinctive GaN/BP heterojunction is proposed, featuring a direct bandgap and advantageous band edge positions conducive to efficient photocatalytic overall water splitting. Under the influence of biaxial strain, the heterojunction type undergoes a transition from direct type-I to direct type-II and Z, augmenting the separation of photoexcited electrons and holes and markedly enhancing the efficiency of photocatalytic hydrogen production. Furthermore, the heterojunction exhibits commendable capabilities in absorbing visible light. This research provides a promising avenue to surmount the constraints associated with monolayer BP in photocatalysis, offering valuable insights for the development of efficient photocatalytic materials.
本研究通过第一原理计算研究了双轴应变对单层黑磷（BP）的影响，证实了其稳定性，并随之改变了其光催化性能。在双轴应变作用下，黑磷显示出直接带隙，适合在水分离过程中光催化制氢，但由于其价带最大边缘的限制。我们提出了一种独特的 GaN/BP 异质结，它具有直接带隙和有利的带边位置，有利于高效的光催化整体水分离。在双轴应变的影响下，异质结类型从直接 I 型过渡到直接 II 型和 Z 型，增强了光激发电子和空穴的分离，显著提高了光催化制氢的效率。此外，该异质结在吸收可见光方面也表现出令人称道的能力。这项研究为克服光催化过程中与单层 BP 相关的限制提供了一条前景广阔的途径，为开发高效光催化材料提供了宝贵的见解。
{"title":"Tailoring band structures and photocatalytic overall water splitting in a two-dimensional GaN/black phosphorus heterojunction: First-principles calculations","authors":"Xiaodong Hao, Qiheng Ma, Xishuo Zhang, Jiahui Wang, Deqiang Yin, Shufang Ma, Bingshe Xu","doi":"10.1063/5.0218663","DOIUrl":"https://doi.org/10.1063/5.0218663","url":null,"abstract":"This study investigates the impact of biaxial strain on monolayer black phosphorus (BP) through first-principles calculations, confirming its stability and subsequently modifying its photocatalytic performance. Under biaxial strain, BP exhibits a direct bandgap suitable for photocatalytic hydrogen production during water splitting, albeit with limitations due to its valence band maximum edge. A distinctive GaN/BP heterojunction is proposed, featuring a direct bandgap and advantageous band edge positions conducive to efficient photocatalytic overall water splitting. Under the influence of biaxial strain, the heterojunction type undergoes a transition from direct type-I to direct type-II and Z, augmenting the separation of photoexcited electrons and holes and markedly enhancing the efficiency of photocatalytic hydrogen production. Furthermore, the heterojunction exhibits commendable capabilities in absorbing visible light. This research provides a promising avenue to surmount the constraints associated with monolayer BP in photocatalysis, offering valuable insights for the development of efficient photocatalytic materials.","PeriodicalId":502933,"journal":{"name":"Journal of Applied Physics","volume":"34 47","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141924555","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}
Alloying with rare earth (RE) elements is an effective way to improve the mechanical properties of the Mg alloys. However, the strengthening mechanism of RE element Y on the Mg alloys still needs to be further revealed. The effect of grain boundary (GB) segregation of RE element Y on the mechanical properties and the GB stability of the Mg alloys are investigated by the molecular dynamics simulation method. The results show that the GB segregation of Y atoms can significantly increase the yield strength and GB stability of the Mg alloys. The higher the content of Y atoms at the GB, the stronger the stability of the GB and the higher the strength of the alloys. The results also show that the GBs thicken significantly with increasing Y content at the GBs, which is attributed to the diffusion of Y atoms, leading to the solid-state amorphization of the Mg alloys. The results indicate that with the increase of Y content at the GBs, the Mg alloys undergo a transition from the plastic deformation dominated by the co-sliding of GBs and dislocations to the slip of dislocations only. This work provides a theoretical basis for the design and preparation of high-performance Mg alloys.
与稀土（RE）元素合金化是改善镁合金机械性能的有效方法。然而，稀土元素 Y 对镁合金的强化机理仍有待进一步揭示。本文采用分子动力学模拟方法研究了 RE 元素 Y 的晶界偏析对镁合金力学性能和晶界稳定性的影响。结果表明，Y 原子的晶界偏析能显著提高镁合金的屈服强度和晶界稳定性。GB 上的 Y 原子含量越高，GB 的稳定性就越强，合金的强度就越高。结果还表明，随着 GB 上 Y 原子含量的增加，GB 明显变厚，这是由于 Y 原子的扩散导致了镁合金的固态非晶化。结果表明，随着 GB 处 Y 含量的增加，镁合金经历了从 GB 和位错共同滑动为主的塑性变形到仅有位错滑动的转变。这项研究为设计和制备高性能镁合金提供了理论依据。
{"title":"Effect of grain boundary segregation of rare earth element on deformation behavior of Mg alloys","authors":"S. Li, H. Y. Song","doi":"10.1063/5.0219468","DOIUrl":"https://doi.org/10.1063/5.0219468","url":null,"abstract":"Alloying with rare earth (RE) elements is an effective way to improve the mechanical properties of the Mg alloys. However, the strengthening mechanism of RE element Y on the Mg alloys still needs to be further revealed. The effect of grain boundary (GB) segregation of RE element Y on the mechanical properties and the GB stability of the Mg alloys are investigated by the molecular dynamics simulation method. The results show that the GB segregation of Y atoms can significantly increase the yield strength and GB stability of the Mg alloys. The higher the content of Y atoms at the GB, the stronger the stability of the GB and the higher the strength of the alloys. The results also show that the GBs thicken significantly with increasing Y content at the GBs, which is attributed to the diffusion of Y atoms, leading to the solid-state amorphization of the Mg alloys. The results indicate that with the increase of Y content at the GBs, the Mg alloys undergo a transition from the plastic deformation dominated by the co-sliding of GBs and dislocations to the slip of dislocations only. This work provides a theoretical basis for the design and preparation of high-performance Mg alloys.","PeriodicalId":502933,"journal":{"name":"Journal of Applied Physics","volume":"44 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141924123","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}
Libo Zhang, Li Ye, Weiwei Zhao, Chongji Huang, Tao Li, Tai Min, Jinbo Yang, Mingliang Tian, Xuegang Chen
Electric field induced time-dependent second harmonic generation (TD-SHG) is an emerging sensitive and non-contact method for qualitatively/quantitatively probing semiconductor parameters. The TD-SHG signal is related to the evolution of the built-in electric field due to laser-induced electron generation and transportation. Here, we conducted a comprehensive study of fixed charge density (Qox) and interface state density (Dit) using the conventional conductance method to compare them with the SHG signal from TD-SHG. The extracted Qox is around 2.49 × 1010 cm−2 regardless of SiO2 thickness, corresponding to the constant SHG intensity at the minimum of TD-SHG. The extracted Dit linearly decreases with the SiO2 thickness, which is related to the linear change of extracted time constant from TD-SHG. Therefore, the TD-SHG, being a sensitive and non-contact method as well as simple and fast, can serve as an alternative approach to test the semiconductor parameters, which may facilitate semiconductor testing.
{"title":"Comprehensive study of interface state via the time-dependent second harmonic generation","authors":"Libo Zhang, Li Ye, Weiwei Zhao, Chongji Huang, Tao Li, Tai Min, Jinbo Yang, Mingliang Tian, Xuegang Chen","doi":"10.1063/5.0188344","DOIUrl":"https://doi.org/10.1063/5.0188344","url":null,"abstract":"Electric field induced time-dependent second harmonic generation (TD-SHG) is an emerging sensitive and non-contact method for qualitatively/quantitatively probing semiconductor parameters. The TD-SHG signal is related to the evolution of the built-in electric field due to laser-induced electron generation and transportation. Here, we conducted a comprehensive study of fixed charge density (Qox) and interface state density (Dit) using the conventional conductance method to compare them with the SHG signal from TD-SHG. The extracted Qox is around 2.49 × 1010 cm−2 regardless of SiO2 thickness, corresponding to the constant SHG intensity at the minimum of TD-SHG. The extracted Dit linearly decreases with the SiO2 thickness, which is related to the linear change of extracted time constant from TD-SHG. Therefore, the TD-SHG, being a sensitive and non-contact method as well as simple and fast, can serve as an alternative approach to test the semiconductor parameters, which may facilitate semiconductor testing.","PeriodicalId":502933,"journal":{"name":"Journal of Applied Physics","volume":"60 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141929233","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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