Michael Lorke, Igor Khanonkin, Stephan Michael, Johann Peter Reithmaier, Gadi Eisenstein, Frank Jahnke
In quantum-dot tunnel-injection lasers, the excited charge carriers are efficiently captured from the bulk states via an injector quantum well and then transferred into the quantum dots via a tunnel barrier. The alignment of the electronic levels is crucial for the high efficiency of these processes and especially for the fast modulation dynamics of these lasers. In particular, the quantum mechanical nature of the tunneling process must be taken into account in the transition from two-dimensional quantum well states to zero-dimensional quantum-dot states. This results in hybrid states, from which the scattering into the quantum-dot ground states takes place. We combine electronic state calculations of the tunnel-injection structures with many-body calculations of the scattering processes and insert this into a complete laser simulator. This allows us to study the influence of the structural design and the resulting electronic states as well as limitations due to inhomogeneous quantum-dot distributions. We find that the optimal electronic state alignment deviates from a simple picture in which the quantum-dot ground state energies are one LO-phonon energy below the injector quantum well ground state.
{"title":"Strategies for the alignment of electronic states in quantum-dot tunnel-injection lasers","authors":"Michael Lorke, Igor Khanonkin, Stephan Michael, Johann Peter Reithmaier, Gadi Eisenstein, Frank Jahnke","doi":"10.1063/5.0228411","DOIUrl":"https://doi.org/10.1063/5.0228411","url":null,"abstract":"In quantum-dot tunnel-injection lasers, the excited charge carriers are efficiently captured from the bulk states via an injector quantum well and then transferred into the quantum dots via a tunnel barrier. The alignment of the electronic levels is crucial for the high efficiency of these processes and especially for the fast modulation dynamics of these lasers. In particular, the quantum mechanical nature of the tunneling process must be taken into account in the transition from two-dimensional quantum well states to zero-dimensional quantum-dot states. This results in hybrid states, from which the scattering into the quantum-dot ground states takes place. We combine electronic state calculations of the tunnel-injection structures with many-body calculations of the scattering processes and insert this into a complete laser simulator. This allows us to study the influence of the structural design and the resulting electronic states as well as limitations due to inhomogeneous quantum-dot distributions. We find that the optimal electronic state alignment deviates from a simple picture in which the quantum-dot ground state energies are one LO-phonon energy below the injector quantum well ground state.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"68 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142718346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fengyue He, Lianjun Wen, Xiyu Hou, Lin-Han Li, Lei Liu, Ran Zhuo, Ping-Heng Tan, Dong Pan, Jianhua Zhao
InSb nanowires (NWs) show an important application in topological quantum computing owing to their high electron mobility, strong spin–orbit interaction, and large g factor. Particularly, ultra-thin InSb NWs are expected to be used to solve the problem of multiple sub-band occupation for the detection of Majorana fermions. However, it is still difficult to epitaxially grow ultra-thin InSb NWs due to the surfactant effect of Sb. Here, we develop an in-plane self-assembled technique to grow catalyst-free ultra-thin InSb NWs on Ge(001) substrates by molecular-beam epitaxy. It is found that ultra-thin InSb NWs with a diameter as small as 17 nm can be obtained by this growth manner. More importantly, these NWs have aspect ratios of 40–100. We also find that the in-plane InSb NWs always grow along the [110] and [11¯0] directions, and they have the same {111} facets, which are caused by the lowest-surface energy of {111} crystal planes for NWs grown with a high Sb/In ratio. Detailed structural studies confirm that InSb NWs are high-quality zinc blende crystals, and there is a strict epitaxial relationship between the InSb NW and the Ge substrate. The in-plane InSb NWs have a similar Raman spectral linewidth compared with that of the single-crystal InSb substrate, further confirming their high crystal quality. Our work provides useful insights into the controlled growth of in-plane catalyst-free III–V NWs.
{"title":"Catalyst-free in-plane growth of high-quality ultra-thin InSb nanowires","authors":"Fengyue He, Lianjun Wen, Xiyu Hou, Lin-Han Li, Lei Liu, Ran Zhuo, Ping-Heng Tan, Dong Pan, Jianhua Zhao","doi":"10.1063/5.0223513","DOIUrl":"https://doi.org/10.1063/5.0223513","url":null,"abstract":"InSb nanowires (NWs) show an important application in topological quantum computing owing to their high electron mobility, strong spin–orbit interaction, and large g factor. Particularly, ultra-thin InSb NWs are expected to be used to solve the problem of multiple sub-band occupation for the detection of Majorana fermions. However, it is still difficult to epitaxially grow ultra-thin InSb NWs due to the surfactant effect of Sb. Here, we develop an in-plane self-assembled technique to grow catalyst-free ultra-thin InSb NWs on Ge(001) substrates by molecular-beam epitaxy. It is found that ultra-thin InSb NWs with a diameter as small as 17 nm can be obtained by this growth manner. More importantly, these NWs have aspect ratios of 40–100. We also find that the in-plane InSb NWs always grow along the [110] and [11¯0] directions, and they have the same {111} facets, which are caused by the lowest-surface energy of {111} crystal planes for NWs grown with a high Sb/In ratio. Detailed structural studies confirm that InSb NWs are high-quality zinc blende crystals, and there is a strict epitaxial relationship between the InSb NW and the Ge substrate. The in-plane InSb NWs have a similar Raman spectral linewidth compared with that of the single-crystal InSb substrate, further confirming their high crystal quality. Our work provides useful insights into the controlled growth of in-plane catalyst-free III–V NWs.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"8 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142718322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fei Zhou, Zhiyuan Yang, Jingtao Huang, Xueping Zheng, Xianhua Wei, Bo Dai
Strong second harmonic generation (SHG) was observed when the two-photon energy matches to the self-trapped exciton resonance states in the lattice inversion symmetric system of two-dimensional (2D) KNbO2 crystals. It is ascribed to the symmetry broken induced by the bending distortion of O−Nb−O in individual octahedrons (low frequency T2g modes) that coupling to the two-photon frequency. The quantum confinement SHG response with more than one orders of enhancement is obtained due to the phonon-exciton-photon interaction with dimension reduction. In addition, the exciton-phonon interaction couples SHG photons to a non-equilibrium energy with a Stokes or anti-Stokes energy splitting of ∼18–21 meV, which is corresponding to the Raman shift of T2g modes.
{"title":"Self-trapped exciton-phonon resonance enhanced nonlinear susceptibility in 2D KNbO2","authors":"Fei Zhou, Zhiyuan Yang, Jingtao Huang, Xueping Zheng, Xianhua Wei, Bo Dai","doi":"10.1063/5.0239364","DOIUrl":"https://doi.org/10.1063/5.0239364","url":null,"abstract":"Strong second harmonic generation (SHG) was observed when the two-photon energy matches to the self-trapped exciton resonance states in the lattice inversion symmetric system of two-dimensional (2D) KNbO2 crystals. It is ascribed to the symmetry broken induced by the bending distortion of O−Nb−O in individual octahedrons (low frequency T2g modes) that coupling to the two-photon frequency. The quantum confinement SHG response with more than one orders of enhancement is obtained due to the phonon-exciton-photon interaction with dimension reduction. In addition, the exciton-phonon interaction couples SHG photons to a non-equilibrium energy with a Stokes or anti-Stokes energy splitting of ∼18–21 meV, which is corresponding to the Raman shift of T2g modes.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"247 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142718389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We investigated the photoluminescence (PL) from single-layer MoS2 on VO2 platelets grown on SiO2, where the insulating and metallic phases can coexist above a bulk transition temperature of 340 K, due to the inhomogeneous strain. We found that the intensity of PL from MoS2 on metallic VO2 is higher than that on the insulating counterpart, resulting in spatially varying PL even at the sub-micrometer scale. In contrast to the intensity, the PL peak energies were observed to be nearly identical on insulating and metallic VO2, indicating that the influences of charge transfer, strain, and dielectric screening on MoS2 are comparable, regardless of the phase state. Thus, the observed difference in PL intensity is due to the difference in refractive indices of insulating and metallic VO2, leading to the phase-dependent Fabry–Pérot interference effect. We performed numerical simulations for the emission from MoS2 supported on the VO2-based Fabry–Pérot interferometer. The calculated emission intensity ratio on insulating and metallic VO2 well reproduces the experimental observations. These results suggest a strategy for controlling PL from two-dimensional semiconductors in a spatial and reconfigurable manner.
{"title":"Spatial and reconfigurable control of photoluminescence from single-layer MoS2 using a strained VO2-based Fabry–Pérot cavity","authors":"Koyo Nakayama, Shota Toida, Takahiko Endo, Mitsuru Inada, Shingo Sato, Hiroshi Tani, Kenji Watanabe, Takashi Taniguchi, Keiji Ueno, Yasumitsu Miyata, Kazunari Matsuda, Mahito Yamamoto","doi":"10.1063/5.0236517","DOIUrl":"https://doi.org/10.1063/5.0236517","url":null,"abstract":"We investigated the photoluminescence (PL) from single-layer MoS2 on VO2 platelets grown on SiO2, where the insulating and metallic phases can coexist above a bulk transition temperature of 340 K, due to the inhomogeneous strain. We found that the intensity of PL from MoS2 on metallic VO2 is higher than that on the insulating counterpart, resulting in spatially varying PL even at the sub-micrometer scale. In contrast to the intensity, the PL peak energies were observed to be nearly identical on insulating and metallic VO2, indicating that the influences of charge transfer, strain, and dielectric screening on MoS2 are comparable, regardless of the phase state. Thus, the observed difference in PL intensity is due to the difference in refractive indices of insulating and metallic VO2, leading to the phase-dependent Fabry–Pérot interference effect. We performed numerical simulations for the emission from MoS2 supported on the VO2-based Fabry–Pérot interferometer. The calculated emission intensity ratio on insulating and metallic VO2 well reproduces the experimental observations. These results suggest a strategy for controlling PL from two-dimensional semiconductors in a spatial and reconfigurable manner.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"65 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142718319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Normal microwave (MW) electromagnetic field detectors convert microwave power into voltages, which results in loss of the vector characteristics of the microwave field. In this work, we developed a MW magnetic field (h-field) vector detector based on the off-resonant spin rectification effect. By measuring and analyzing the angle dependence of the rectification voltages under off-resonant conditions, we can extract the three components of the h-field. As an initial test of this method, we obtained the h-field distributions at 5.4 GHz generated by a coplanar waveguide with sub-wavelength resolution. Compared to methods using ferromagnetic resonance, this technique offers a faster and more convenient way to determine the spatial distribution of the h-field, which can be used for MW integrated circuit optimization and fault diagnosis.
{"title":"Microwave field vector detector based on the off-resonant spin rectification effect","authors":"Peiwen Luo, Bin Peng, Wanli Zhang, Wenxu Zhang","doi":"10.1063/5.0245019","DOIUrl":"https://doi.org/10.1063/5.0245019","url":null,"abstract":"Normal microwave (MW) electromagnetic field detectors convert microwave power into voltages, which results in loss of the vector characteristics of the microwave field. In this work, we developed a MW magnetic field (h-field) vector detector based on the off-resonant spin rectification effect. By measuring and analyzing the angle dependence of the rectification voltages under off-resonant conditions, we can extract the three components of the h-field. As an initial test of this method, we obtained the h-field distributions at 5.4 GHz generated by a coplanar waveguide with sub-wavelength resolution. Compared to methods using ferromagnetic resonance, this technique offers a faster and more convenient way to determine the spatial distribution of the h-field, which can be used for MW integrated circuit optimization and fault diagnosis.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"108 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142718382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Davide Costa, Lucas E. A. Stehouwer, Yi Huang, Sara Martí-Sánchez, Davide Degli Esposti, Jordi Arbiol, Giordano Scappucci
We investigate the disorder properties of two-dimensional hole gases in Ge/SiGe heterostructures grown on Ge wafers, using thick SiGe barriers to mitigate the influence of the semiconductor–dielectric interface. Across several heterostructure field effect transistors, we measure an average maximum mobility of (4.4±0.2)×106 cm2/Vs at a saturation density of (1.72±0.03)×1011 cm−2, corresponding to a long mean free path of (30±1)μm. The highest measured mobility is 4.68×106 cm2/Vs. We identify uniform background impurities and interface roughness as the dominant scattering mechanisms limiting mobility in a representative device, and we evaluate a percolation-induced critical density of (4.5±0.1)×109 cm−2. This low-disorder heterostructure, according to simulations, may support the electrostatic confinement of holes in gate-defined quantum dots.
{"title":"Reducing disorder in Ge quantum wells by using thick SiGe barriers","authors":"Davide Costa, Lucas E. A. Stehouwer, Yi Huang, Sara Martí-Sánchez, Davide Degli Esposti, Jordi Arbiol, Giordano Scappucci","doi":"10.1063/5.0242746","DOIUrl":"https://doi.org/10.1063/5.0242746","url":null,"abstract":"We investigate the disorder properties of two-dimensional hole gases in Ge/SiGe heterostructures grown on Ge wafers, using thick SiGe barriers to mitigate the influence of the semiconductor–dielectric interface. Across several heterostructure field effect transistors, we measure an average maximum mobility of (4.4±0.2)×106 cm2/Vs at a saturation density of (1.72±0.03)×1011 cm−2, corresponding to a long mean free path of (30±1)μm. The highest measured mobility is 4.68×106 cm2/Vs. We identify uniform background impurities and interface roughness as the dominant scattering mechanisms limiting mobility in a representative device, and we evaluate a percolation-induced critical density of (4.5±0.1)×109 cm−2. This low-disorder heterostructure, according to simulations, may support the electrostatic confinement of holes in gate-defined quantum dots.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"123 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142718318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The investigation of non-equilibrium carrier dynamics in two-dimensional semi-metallic materials, particularly at low temperatures, is crucial for elucidating their fundamental properties, including carrier–carrier interactions and electron–phonon scattering mechanisms. In this study, we examine the behavior of 1T-TiS2, utilizing scanning photocurrent microscopy, bias voltage-adjustable photoresponse measurements, and pump-probe techniques to explore the temperature-dependent transport and relaxation of photo-excited charge carriers. We observe a non-monotonic intrinsic photocurrent in the biased device, with a pronounced peak feature occurring at approximately 25 K, which is corroborated by pump-probe measurements that reveal a similar peak in the magnitude and relaxation time of the differential reflectance as a function of the temperature. Our results highlight the unique carrier dynamics in TiS2, offering valuable insights for the design of TiS2-based optoelectronic devices that can operate effectively across a wide temperature range.
{"title":"Low-temperature transport and relaxation of photo-carriers in TiS2","authors":"Ruan Zhang, Shuangxing Zhu, Chaofan Wang, Jiaxin Wu, Junning Mei, Ying Liu, Yu Chen, Qiyi Wu, Chen Zhang, Mingyuan Huang, Jianqiao Meng, Xinghan Cai","doi":"10.1063/5.0235742","DOIUrl":"https://doi.org/10.1063/5.0235742","url":null,"abstract":"The investigation of non-equilibrium carrier dynamics in two-dimensional semi-metallic materials, particularly at low temperatures, is crucial for elucidating their fundamental properties, including carrier–carrier interactions and electron–phonon scattering mechanisms. In this study, we examine the behavior of 1T-TiS2, utilizing scanning photocurrent microscopy, bias voltage-adjustable photoresponse measurements, and pump-probe techniques to explore the temperature-dependent transport and relaxation of photo-excited charge carriers. We observe a non-monotonic intrinsic photocurrent in the biased device, with a pronounced peak feature occurring at approximately 25 K, which is corroborated by pump-probe measurements that reveal a similar peak in the magnitude and relaxation time of the differential reflectance as a function of the temperature. Our results highlight the unique carrier dynamics in TiS2, offering valuable insights for the design of TiS2-based optoelectronic devices that can operate effectively across a wide temperature range.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"21 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142718378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y. Liu, X. Jin, H. Jung, S. Lee, F. Harun, J. S. Ng, S. Krishna, J. P. R. David
The application of an electric field to a semiconductor can alter its absorption properties. This electroabsorption effect can have a significant impact on the quantum efficiency of detector structures. The photocurrents in bulk InGaAs and GaAsSb p-i-n photodiodes with intrinsic absorber layer thicknesses ranging from 1 to 4.8 μm have been investigated. By using phase-sensitive photocurrent measurements as a function of wavelength, the absorption coefficients as low as 1 cm−1 were extracted for electric fields up to 200 kV/cm. Our findings show that while the absorption coefficients reduce between 1500 and 1650 nm for both materials when subject to an increasing electric field, an absorption coefficient of 100 cm−1 can be obtained at a wavelength of 2 μm, well beyond the bandgap energy when they are subject to a high electric field. The results are shown to be in good agreement with theoretical models that use Airy functions to solve the absorption coefficients in a uniform electric field.
{"title":"Electroabsorption in InGaAs and GaAsSb p-i-n photodiodes","authors":"Y. Liu, X. Jin, H. Jung, S. Lee, F. Harun, J. S. Ng, S. Krishna, J. P. R. David","doi":"10.1063/5.0228938","DOIUrl":"https://doi.org/10.1063/5.0228938","url":null,"abstract":"The application of an electric field to a semiconductor can alter its absorption properties. This electroabsorption effect can have a significant impact on the quantum efficiency of detector structures. The photocurrents in bulk InGaAs and GaAsSb p-i-n photodiodes with intrinsic absorber layer thicknesses ranging from 1 to 4.8 μm have been investigated. By using phase-sensitive photocurrent measurements as a function of wavelength, the absorption coefficients as low as 1 cm−1 were extracted for electric fields up to 200 kV/cm. Our findings show that while the absorption coefficients reduce between 1500 and 1650 nm for both materials when subject to an increasing electric field, an absorption coefficient of 100 cm−1 can be obtained at a wavelength of 2 μm, well beyond the bandgap energy when they are subject to a high electric field. The results are shown to be in good agreement with theoretical models that use Airy functions to solve the absorption coefficients in a uniform electric field.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"180 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142718384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The internal strain in practical materials is usually seen as defects and a large of methods have been proposed to avoid its appearance. However, strains in magnetic materials can be effective in regulating the performance mediated by magnetoelastic coupling effect. Herein, we theoretically demonstrate the motion of skyrmions driven by time-dependent periodical strains which imitate strain fluctuations in real materials. It is found that the motion acceleration of skyrmions is exponential correlation with diameters and skyrmions can be rebounded near the end of magnetic racetrack for larger size of diameters. Such a motion results from the excitation of spin wave modes on the position of circular domain walls in skyrmions. Our results can provide insight for manipulating skyrmions by strain engineering for applications in information storage and processing.
{"title":"Exponential dependence between motion acceleration and diameters of skyrmions under the driven of periodical strains","authors":"Hailuo Wu, Rongzhi Zhao, Yixing Li, Xuefeng Zhang","doi":"10.1063/5.0232670","DOIUrl":"https://doi.org/10.1063/5.0232670","url":null,"abstract":"The internal strain in practical materials is usually seen as defects and a large of methods have been proposed to avoid its appearance. However, strains in magnetic materials can be effective in regulating the performance mediated by magnetoelastic coupling effect. Herein, we theoretically demonstrate the motion of skyrmions driven by time-dependent periodical strains which imitate strain fluctuations in real materials. It is found that the motion acceleration of skyrmions is exponential correlation with diameters and skyrmions can be rebounded near the end of magnetic racetrack for larger size of diameters. Such a motion results from the excitation of spin wave modes on the position of circular domain walls in skyrmions. Our results can provide insight for manipulating skyrmions by strain engineering for applications in information storage and processing.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"180 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142718315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tunable ferroelectric film capacitors play an important role in tunable microwave devices and filter systems due to their high dielectric constant, low loss, and high dielectric tunability. However, there is a trade-off between low loss and high tunability, which limits further enhancement of dielectric performance. Here, we propose an ultra-tunable capacitor by designing a Ba0.7Sr0.3TiO3 (BST)–semiconductor heterostructure. In the tunable capacitor, the BST film is fabricated directly on p-type silicon substrates by magnetron sputtering, and a heterostructure layer is constructed. The coupling effects between the semiconductor depletion layer capacitance and the BST capacitance produce higher capacitance tunability than a traditional sandwich BST capacitor. Based on the coupling effects, a metal–ferroelectric–semiconductor–ferroelectric–metal capacitor is developed, which enables the capacitor to operate under both negative and positive biases, which has an n value (n=Cmax/Cmin) of 90 with 40 V bias voltage and a maximum Q of 1000. The results offer a potential approach to designing high-performance tunable capacitors on silicon with BST film that could build tunable filters for information processing in communication systems.
可调谐铁电薄膜电容器具有高介电常数、低损耗和高介电可调谐性，因此在可调谐微波器件和滤波器系统中发挥着重要作用。然而，低损耗和高可调谐性之间存在权衡，这限制了介电性能的进一步提高。在此，我们通过设计 Ba0.7Sr0.3TiO3 (BST) - 半导体异质结构，提出了一种超可调电容器。在这种可调谐电容器中，BST 薄膜是通过磁控溅射直接在 p 型硅衬底上制作的，并构建了一个异质结构层。与传统的夹层 BST 电容器相比，半导体耗尽层电容和 BST 电容之间的耦合效应产生了更高的电容可调谐性。基于这种耦合效应，我们开发出了一种金属-铁电-半导体-铁电-金属电容器，它能使电容器在负偏压和正偏压下工作，在 40 V 偏置电压下的 n 值（n=Cmax/Cmin）为 90，最大 Q 值为 1000。这些结果为在硅上设计带有 BST 薄膜的高性能可调谐电容器提供了一种潜在的方法，这种电容器可以为通信系统中的信息处理构建可调谐滤波器。
{"title":"Ultra-tunable dielectric capacitors enhanced by coupling ferroelectric field effect and semiconductor field effect","authors":"Feilong Mao, Jiashu Gui, Yongqi Hou, Siyuan Gao, Haohan Zeng, Weibiao Wang, Zhibin Xu, Yifan Zhu, Li Fan, Hui Zhang","doi":"10.1063/5.0227237","DOIUrl":"https://doi.org/10.1063/5.0227237","url":null,"abstract":"Tunable ferroelectric film capacitors play an important role in tunable microwave devices and filter systems due to their high dielectric constant, low loss, and high dielectric tunability. However, there is a trade-off between low loss and high tunability, which limits further enhancement of dielectric performance. Here, we propose an ultra-tunable capacitor by designing a Ba0.7Sr0.3TiO3 (BST)–semiconductor heterostructure. In the tunable capacitor, the BST film is fabricated directly on p-type silicon substrates by magnetron sputtering, and a heterostructure layer is constructed. The coupling effects between the semiconductor depletion layer capacitance and the BST capacitance produce higher capacitance tunability than a traditional sandwich BST capacitor. Based on the coupling effects, a metal–ferroelectric–semiconductor–ferroelectric–metal capacitor is developed, which enables the capacitor to operate under both negative and positive biases, which has an n value (n=Cmax/Cmin) of 90 with 40 V bias voltage and a maximum Q of 1000. The results offer a potential approach to designing high-performance tunable capacitors on silicon with BST film that could build tunable filters for information processing in communication systems.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"1 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142696881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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