Kang Fu, Wenxuan Wu, Ziqi Ye, Jianwei Fu, Jiabin Yan, Fan Shi, Wei Cai, Yongjin Wang
GaN-based quantum well diodes (QWDs) exhibit the physical phenomenon of simultaneous emission and detection, offering a promising pathway toward compact, multifunctional optoelectronic platforms. We present a wearable joint flexion sensing system based on a dual-QWD chip operating at ∼460 nm. One QWD serves as a stable light emitter, while the other detects local optical field changes induced by joint bending. The chip is integrated onto a flexible printed circuit board and worn on the outer side of joints such as the elbow, wrist, and fingers, providing good skin compatibility and thermal safety. Optical signal variations are processed using a multilayer perceptron model to classify six hand gestures, including finger-count patterns and a clenched fist. A fivefold cross-validation confirms gesture recognition accuracies exceeding 97% across all categories. This work demonstrates a compact and reliable real-time gesture sensing method, underscoring the potential of GaN-based QWDs in next-generation wearable interactive systems.
{"title":"Dual-function GaN QWD chip for real-time joint flexion and gesture recognition","authors":"Kang Fu, Wenxuan Wu, Ziqi Ye, Jianwei Fu, Jiabin Yan, Fan Shi, Wei Cai, Yongjin Wang","doi":"10.1063/5.0314878","DOIUrl":"https://doi.org/10.1063/5.0314878","url":null,"abstract":"GaN-based quantum well diodes (QWDs) exhibit the physical phenomenon of simultaneous emission and detection, offering a promising pathway toward compact, multifunctional optoelectronic platforms. We present a wearable joint flexion sensing system based on a dual-QWD chip operating at ∼460 nm. One QWD serves as a stable light emitter, while the other detects local optical field changes induced by joint bending. The chip is integrated onto a flexible printed circuit board and worn on the outer side of joints such as the elbow, wrist, and fingers, providing good skin compatibility and thermal safety. Optical signal variations are processed using a multilayer perceptron model to classify six hand gestures, including finger-count patterns and a clenched fist. A fivefold cross-validation confirms gesture recognition accuracies exceeding 97% across all categories. This work demonstrates a compact and reliable real-time gesture sensing method, underscoring the potential of GaN-based QWDs in next-generation wearable interactive systems.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"5 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147578030","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}
Nonreciprocal thermal radiation, which breaks Kirchhoff's law by decoupling absorptivity and emissivity, is essential for advanced radiative heat transfer control. However, achieving broadband and tunable nonreciprocal thermal radiation with high design efficiency remains a challenge. This study proposes a novel hybrid deep learning framework, integrating the Artificial Rabbit Optimization and tandem neural network, to inversely design multilayer films (MLFs) based on magnetized gradient epsilon-near-zero (ENZ) InAs layers. By using the Artificial Rabbit Optimization algorithm, we collect a high-quality dataset with a noise ratio of only 3.2%, significantly reducing computational overhead compared to random sampling. The multitasking tandem neural network converges to a low cost function of 0.086, improving the accuracy and avoiding the scattering problem faced by traditional neural networks. Results show that significant nonreciprocal thermal radiation (nonreciprocity > 0.637 and peak 0.723) is achieved in the 14–19 μm range by exploiting the magneto-optical effects of InAs and ENZ-induced Brewster modes. Furthermore, the MLFs exhibit reversed absorptivity and emissivity spectra under reversed magnetic fields. These findings provide a data-efficient and scalable solution for dynamic thermal management and infrared camouflage, demonstrating the powerful synergy between deep learning and nonreciprocal photonics.
{"title":"Inverse design epsilon-near-zero-based broadband nonreciprocal thermal emitter using hybrid deep learning framework","authors":"Jun-Yang Sui, Hai-Feng Zhang","doi":"10.1063/5.0323320","DOIUrl":"https://doi.org/10.1063/5.0323320","url":null,"abstract":"Nonreciprocal thermal radiation, which breaks Kirchhoff's law by decoupling absorptivity and emissivity, is essential for advanced radiative heat transfer control. However, achieving broadband and tunable nonreciprocal thermal radiation with high design efficiency remains a challenge. This study proposes a novel hybrid deep learning framework, integrating the Artificial Rabbit Optimization and tandem neural network, to inversely design multilayer films (MLFs) based on magnetized gradient epsilon-near-zero (ENZ) InAs layers. By using the Artificial Rabbit Optimization algorithm, we collect a high-quality dataset with a noise ratio of only 3.2%, significantly reducing computational overhead compared to random sampling. The multitasking tandem neural network converges to a low cost function of 0.086, improving the accuracy and avoiding the scattering problem faced by traditional neural networks. Results show that significant nonreciprocal thermal radiation (nonreciprocity > 0.637 and peak 0.723) is achieved in the 14–19 μm range by exploiting the magneto-optical effects of InAs and ENZ-induced Brewster modes. Furthermore, the MLFs exhibit reversed absorptivity and emissivity spectra under reversed magnetic fields. These findings provide a data-efficient and scalable solution for dynamic thermal management and infrared camouflage, demonstrating the powerful synergy between deep learning and nonreciprocal photonics.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"18 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147578034","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}
Jiale Zheng, Chenhao Zhou, Guo Yang, Kai Leong Chong, Quan Zhou, Xiao Ling, Jianhua Zhang
High-energy ions and metal debris generated by extreme ultraviolet (EUV) light sources pose a severe threat to collector optics. This study demonstrates a hybrid mitigation strategy that combines a helium buffer gas jet with a segmented Halbach cylinder to suppress debris from a discharge-produced plasma source. A semi-analytical model incorporating finite-length effects was developed to optimize the magnetic topology, achieving a central field strength exceeding 0.85 T for magnetic mitigation. Scanning electron microscopy and atomic force microscopy reveal a pristine witness surface with a 36% reduction in roughness compared to the non-magnetic case. In situ quartz crystal microbalance measurements demonstrate that the magnetic field alone reduces debris mass deposition by approximately 69%. Furthermore, unlike heavier buffer gases, the helium jet stabilizes mitigation performance with minimal in-band EUV absorption. These results establish the combined jet–magnetic scheme as a compact, high-efficiency solution for next-generation lithography sources.
{"title":"Debris mitigation of a Xe discharge-produced plasma source combined gas jet and Halbach cylinder","authors":"Jiale Zheng, Chenhao Zhou, Guo Yang, Kai Leong Chong, Quan Zhou, Xiao Ling, Jianhua Zhang","doi":"10.1063/5.0318617","DOIUrl":"https://doi.org/10.1063/5.0318617","url":null,"abstract":"High-energy ions and metal debris generated by extreme ultraviolet (EUV) light sources pose a severe threat to collector optics. This study demonstrates a hybrid mitigation strategy that combines a helium buffer gas jet with a segmented Halbach cylinder to suppress debris from a discharge-produced plasma source. A semi-analytical model incorporating finite-length effects was developed to optimize the magnetic topology, achieving a central field strength exceeding 0.85 T for magnetic mitigation. Scanning electron microscopy and atomic force microscopy reveal a pristine witness surface with a 36% reduction in roughness compared to the non-magnetic case. In situ quartz crystal microbalance measurements demonstrate that the magnetic field alone reduces debris mass deposition by approximately 69%. Furthermore, unlike heavier buffer gases, the helium jet stabilizes mitigation performance with minimal in-band EUV absorption. These results establish the combined jet–magnetic scheme as a compact, high-efficiency solution for next-generation lithography sources.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"32 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147524427","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}
Jiayin He, Xin Wang, Ju Gao, Chen Wang, Ziheng Liu, Wenbo Xia, Hongjie Peng, Chengkang Ao, Hongyue Wang, Jinyan Wang
This Letter investigates the transient extension process of the off-state depletion region along the channel in SiO2-passivated GaN HEMTs based on a channel-probe branch structure. An SiO2 passivation layer was deposited to partially suppress the surface traps and decelerate the dynamic extension process of the depletion region, facilitating measurements of the extension time of the depletion region (τext) at various probe distances (Ldp) under identical off-state conditions. For Ldp < 4 μm, the depletion region extended quickly, then it slowed down and extended with a saturated extension rate for Ldp > 4 μm. Technology Computer Aided Design simulation was performed to help understand the transient extension process of the depletion region. An exponential dependence of τext on the drain–gate bias (VDG) was also observed, which is due to the Poole–Frenkel emission-dominated surface trapping process under off-state conditions. The steady-state potential profile along the channel is also discussed.
{"title":"Transient extension process of the off-state depletion region in GaN HEMTs with SiO2 passivation","authors":"Jiayin He, Xin Wang, Ju Gao, Chen Wang, Ziheng Liu, Wenbo Xia, Hongjie Peng, Chengkang Ao, Hongyue Wang, Jinyan Wang","doi":"10.1063/5.0290603","DOIUrl":"https://doi.org/10.1063/5.0290603","url":null,"abstract":"This Letter investigates the transient extension process of the off-state depletion region along the channel in SiO2-passivated GaN HEMTs based on a channel-probe branch structure. An SiO2 passivation layer was deposited to partially suppress the surface traps and decelerate the dynamic extension process of the depletion region, facilitating measurements of the extension time of the depletion region (τext) at various probe distances (Ldp) under identical off-state conditions. For Ldp &lt; 4 μm, the depletion region extended quickly, then it slowed down and extended with a saturated extension rate for Ldp &gt; 4 μm. Technology Computer Aided Design simulation was performed to help understand the transient extension process of the depletion region. An exponential dependence of τext on the drain–gate bias (VDG) was also observed, which is due to the Poole–Frenkel emission-dominated surface trapping process under off-state conditions. The steady-state potential profile along the channel is also discussed.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"56 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147524017","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 conduction efficiency and reliability of photoconductive semiconductor switches (PCSSs) are strongly influenced by the resistivity of semi-insulating 4H-SiC substrates. In this work, PCSSs fabricated on four 4H-SiC substrates with resistivities ranging from 2.59 × 1011 to >1 × 1012 Ω cm were evaluated under intrinsic excitation (355 nm) and high-voltage, high-repetition operation. All devices exhibit similar optical saturation behavior and comparable switching speed, indicating consistent optical absorption and intrinsic response. In contrast, pronounced differences in conduction stability and degradation behavior emerge under high electric fields and high repetition rates. Under saturated excitation, the low-resistivity device achieves a voltage-conversion efficiency of 99.3%. It also delivers a stable 10 MW peak output for 35 min at 500 Hz, corresponding to more than 106 switching cycles. In comparison, devices fabricated on higher-resistivity substrates exhibit accelerated output decay and more severe electrode degradation. Technology Computer Aided Design simulations yield conduction characteristics consistent with the experimental observations. These results highlight the critical role of substrate resistivity of intrinsically triggered 4H-SiC PCSSs and provide guidance for material selection in high-voltage fast-pulse switching applications.
{"title":"Impact of substrate resistivity on the high-power and long-lifetime conduction characteristics of intrinsically triggered 4H-SiC PCSS","authors":"Xianchao Yu, Xun Sun, Guanglei Zhong, Yangfan Li, Fangbo Zheng, Mengqiao Hu, Duanxi Wu, Longfei Xiao, Chongbiao Luan, Xiufang Chen, Hongtao Li, Xiangang Xu","doi":"10.1063/5.0316766","DOIUrl":"https://doi.org/10.1063/5.0316766","url":null,"abstract":"The conduction efficiency and reliability of photoconductive semiconductor switches (PCSSs) are strongly influenced by the resistivity of semi-insulating 4H-SiC substrates. In this work, PCSSs fabricated on four 4H-SiC substrates with resistivities ranging from 2.59 × 1011 to &gt;1 × 1012 Ω cm were evaluated under intrinsic excitation (355 nm) and high-voltage, high-repetition operation. All devices exhibit similar optical saturation behavior and comparable switching speed, indicating consistent optical absorption and intrinsic response. In contrast, pronounced differences in conduction stability and degradation behavior emerge under high electric fields and high repetition rates. Under saturated excitation, the low-resistivity device achieves a voltage-conversion efficiency of 99.3%. It also delivers a stable 10 MW peak output for 35 min at 500 Hz, corresponding to more than 106 switching cycles. In comparison, devices fabricated on higher-resistivity substrates exhibit accelerated output decay and more severe electrode degradation. Technology Computer Aided Design simulations yield conduction characteristics consistent with the experimental observations. These results highlight the critical role of substrate resistivity of intrinsically triggered 4H-SiC PCSSs and provide guidance for material selection in high-voltage fast-pulse switching applications.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"229 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147524018","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}
Yifei Li, Weizong Wang, Wei Liu, Guangchuan Zhang, Yuankai Yang
The low-frequency plasma oscillations in a wall-less Hall thruster are investigated via three-dimensional particle-in-cell-Monte Carlo collision simulations. The breathing oscillation exhibits three-dimensional azimuthal non-uniformity, initiating from a localized ionization onset region. Ionization subsequently propagates in the −E × B direction and, more rapidly, in the E × B direction due to electron drift, covering the anode surface in an extremely short time. Azimuthally, rotating spokes show structural variation with axial position: near the anode, ionization stably rotates toward regions of higher neutral density, while farther axially, spokes connect radially to the central ionization zone and rotate synchronously. These results underscore the intrinsic three-dimensionality of both axial and azimuthal oscillations in E × B devices with three-dimensional magnetic fields.
{"title":"Three-dimensional inhomogeneous characteristics of low-frequency plasma oscillations in wall-less Hall thrusters","authors":"Yifei Li, Weizong Wang, Wei Liu, Guangchuan Zhang, Yuankai Yang","doi":"10.1063/5.0324411","DOIUrl":"https://doi.org/10.1063/5.0324411","url":null,"abstract":"The low-frequency plasma oscillations in a wall-less Hall thruster are investigated via three-dimensional particle-in-cell-Monte Carlo collision simulations. The breathing oscillation exhibits three-dimensional azimuthal non-uniformity, initiating from a localized ionization onset region. Ionization subsequently propagates in the −E × B direction and, more rapidly, in the E × B direction due to electron drift, covering the anode surface in an extremely short time. Azimuthally, rotating spokes show structural variation with axial position: near the anode, ionization stably rotates toward regions of higher neutral density, while farther axially, spokes connect radially to the central ionization zone and rotate synchronously. These results underscore the intrinsic three-dimensionality of both axial and azimuthal oscillations in E × B devices with three-dimensional magnetic fields.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"26 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147524019","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}
Jianan Song, Zequan Chen, Yuxin Du, Yixin Xiong, Rongming Chu, Miaomiao Jin
GaN junction field-effect transistors (JFETs) were fabricated and subjected to 333.7 MeV gold (Au) ion irradiation to investigate the effects of swift heavy ions on device performance. Electrical characterization following irradiation revealed a significant and permanent increase in off-state leakage current. The leakage was attributed to a vertical conduction mechanism, likely to originate from latent ion tracks formed within the device during SHI exposure. The results indicate a latent track-induced vertical leakage path in GaN JFETs under SHI irradiation. Temperature-dependent current–voltage measurements indicated a voltage-dependent activation energy, suggesting a field-assisted transport process. Device simulations reproduced the experimental leakage behavior and identified the critical leakage path at the p+-GaN/p-GaN region, where the local electric field is most intense. The conduction mechanism was found to be consistent with the Poole–Frenkel emission model, from which a barrier height of approximately 0.38 eV was extracted. These findings offer insights into SHI-induced degradation in GaN devices and provide guidance for designing radiation-hardened GaN electronics for space applications.
{"title":"Study of leakage current in GaN junction field-effect transistor under heavy ion radiation","authors":"Jianan Song, Zequan Chen, Yuxin Du, Yixin Xiong, Rongming Chu, Miaomiao Jin","doi":"10.1063/5.0313387","DOIUrl":"https://doi.org/10.1063/5.0313387","url":null,"abstract":"GaN junction field-effect transistors (JFETs) were fabricated and subjected to 333.7 MeV gold (Au) ion irradiation to investigate the effects of swift heavy ions on device performance. Electrical characterization following irradiation revealed a significant and permanent increase in off-state leakage current. The leakage was attributed to a vertical conduction mechanism, likely to originate from latent ion tracks formed within the device during SHI exposure. The results indicate a latent track-induced vertical leakage path in GaN JFETs under SHI irradiation. Temperature-dependent current–voltage measurements indicated a voltage-dependent activation energy, suggesting a field-assisted transport process. Device simulations reproduced the experimental leakage behavior and identified the critical leakage path at the p+-GaN/p-GaN region, where the local electric field is most intense. The conduction mechanism was found to be consistent with the Poole–Frenkel emission model, from which a barrier height of approximately 0.38 eV was extracted. These findings offer insights into SHI-induced degradation in GaN devices and provide guidance for designing radiation-hardened GaN electronics for space applications.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"44 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147524020","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}
Md. Rezoanur Rahman, Caleb Stamper, Kyle A. Portwin, Xiaolin Wang, Richard A. Mole, Pablo Galaviz, Aiswarya Pradeepkumar, Kirrily C. Rule, Dehong Yu, David L. Cortie
Powder-averaged inelastic neutron spectroscopy was performed in order to compare the phonons of microdiamond, few-layer graphene, and amorphous carbon fibers at room temperature. Both acoustic and optical phonons were observed in the crystalline allotropes. We present average group velocities, phonon densities of states, and heat capacities relevant to intrinsic thermal transport. High-temperature measurements were performed to evaluate whether quasiparticle broadening from phonon–phonon scattering could be detected. The glassy carbon form in the fibers exhibits pronounced spectral broadening and an enhanced low-energy density of states beyond the Debye prediction. Methods for estimating thermal conductivity using inelastic neutron data as input to the phonon-gas model are discussed. We highlight opportunities and challenges for employing higher-resolution methods to directly determine phonon lifetimes.
{"title":"Comparing the phonons and vibrations in carbon allotropes with neutron spectroscopy: Microdiamond, few-layer graphene, and amorphous fibers","authors":"Md. Rezoanur Rahman, Caleb Stamper, Kyle A. Portwin, Xiaolin Wang, Richard A. Mole, Pablo Galaviz, Aiswarya Pradeepkumar, Kirrily C. Rule, Dehong Yu, David L. Cortie","doi":"10.1063/5.0314605","DOIUrl":"https://doi.org/10.1063/5.0314605","url":null,"abstract":"Powder-averaged inelastic neutron spectroscopy was performed in order to compare the phonons of microdiamond, few-layer graphene, and amorphous carbon fibers at room temperature. Both acoustic and optical phonons were observed in the crystalline allotropes. We present average group velocities, phonon densities of states, and heat capacities relevant to intrinsic thermal transport. High-temperature measurements were performed to evaluate whether quasiparticle broadening from phonon–phonon scattering could be detected. The glassy carbon form in the fibers exhibits pronounced spectral broadening and an enhanced low-energy density of states beyond the Debye prediction. Methods for estimating thermal conductivity using inelastic neutron data as input to the phonon-gas model are discussed. We highlight opportunities and challenges for employing higher-resolution methods to directly determine phonon lifetimes.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"18 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147524022","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}
Chinmay Barman, Sandeep Kumar Chinthala, Sai Prasad Goud R., S. V. S. Nageswara Rao, Venugopal Rao Soma, Sai Santosh Kumar Raavi
Charge transport in metal halide perovskites is strongly limited by electron–phonon coupling (EPC) and trap-assisted recombination, which together hinder carrier mobility and device efficiency. Therefore, precise control of EPC strength is crucial for realizing high-performance optoelectronic devices, such as photodetectors. Here, we demonstrate a strategy to overcome these limitations by suppressing Fröhlich electron–phonon coupling in CsPbBr3 nanocrystals through strategic Ag-doping. Low temperature photoluminescence data reveal a dramatic suppression of the Fröhlich interaction, with the EPC strength narrowing from 85.1 ± 8.2 to 45.3 ± 6.1 meV, accompanied by a reduced activation energy upon Ag incorporation. This suppression of phonon-mediated dissipation is further validated by ultrafast transient absorption studies, which reveals significantly prolonged ground-state bleach recovery and extended carrier lifetimes. Consequently, Ag-doped photodetectors exhibit a record detectivity of ∼8.4 × 1013 Jones, an on/off ratio of ∼107, and a fourfold enhancement in the responsivity (0.64 A/W). The near-unity photocurrent behavior with intensity (exponent of 0.98), along with emission behavior, confirms Ag-doping passivates defects and improves carrier extraction. These results establish a strong correlation between lattice engineering and macroscopic device physics, offering a scalable route to high-performance, phonon-managed perovskite optoelectronics.
金属卤化物钙钛矿中的电荷输运受到电子-声子耦合（EPC）和陷阱辅助复合的强烈限制，它们共同阻碍了载流子迁移率和器件效率。因此，精确控制EPC强度对于实现高性能光电器件（如光电探测器）至关重要。在这里，我们展示了一种克服这些限制的策略，即通过战略性ag掺杂抑制CsPbBr3纳米晶体中的Fröhlich电子-声子耦合。低温光致发光数据显示Fröhlich相互作用受到明显抑制，EPC强度从85.1±8.2缩小到45.3±6.1 meV，同时Ag掺入后活化能降低。这种抑制声子介导的耗散被超快瞬态吸收研究进一步证实，这表明基态漂白回收率显著延长，载流子寿命延长。因此，掺银光电探测器表现出创纪录的探测率为~ 8.4 × 1013琼斯，开/关比为~ 107，响应率提高了四倍（0.64 a /W）。接近统一的光电流行为（强度指数为0.98）以及发射行为证实了ag掺杂钝化了缺陷并改善了载流子的提取。这些结果建立了晶格工程和宏观器件物理之间的强相关性，为高性能声子管理钙钛矿光电子学提供了可扩展的途径。
{"title":"Suppressed electron–phonon coupling in Ag-doped CsPbBr3 for high-performance photodetectors","authors":"Chinmay Barman, Sandeep Kumar Chinthala, Sai Prasad Goud R., S. V. S. Nageswara Rao, Venugopal Rao Soma, Sai Santosh Kumar Raavi","doi":"10.1063/5.0321026","DOIUrl":"https://doi.org/10.1063/5.0321026","url":null,"abstract":"Charge transport in metal halide perovskites is strongly limited by electron–phonon coupling (EPC) and trap-assisted recombination, which together hinder carrier mobility and device efficiency. Therefore, precise control of EPC strength is crucial for realizing high-performance optoelectronic devices, such as photodetectors. Here, we demonstrate a strategy to overcome these limitations by suppressing Fröhlich electron–phonon coupling in CsPbBr3 nanocrystals through strategic Ag-doping. Low temperature photoluminescence data reveal a dramatic suppression of the Fröhlich interaction, with the EPC strength narrowing from 85.1 ± 8.2 to 45.3 ± 6.1 meV, accompanied by a reduced activation energy upon Ag incorporation. This suppression of phonon-mediated dissipation is further validated by ultrafast transient absorption studies, which reveals significantly prolonged ground-state bleach recovery and extended carrier lifetimes. Consequently, Ag-doped photodetectors exhibit a record detectivity of ∼8.4 × 1013 Jones, an on/off ratio of ∼107, and a fourfold enhancement in the responsivity (0.64 A/W). The near-unity photocurrent behavior with intensity (exponent of 0.98), along with emission behavior, confirms Ag-doping passivates defects and improves carrier extraction. These results establish a strong correlation between lattice engineering and macroscopic device physics, offering a scalable route to high-performance, phonon-managed perovskite optoelectronics.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"90 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147524062","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}
Yan Wang, Zhigao Xie, Yizhang Guan, Jiahe Cao, Yibo Zhang, Guofeng Hu, Yu Bai, Yew Hoong Wong, Guosong Zeng, Zhiqiang Huang, Chee Keong Tan
Advancing polarization control in semiconductors is pivotal for next-generation electronics, enabling revolutionary advances in energy and industrial systems. The metastable ε-Ga2O3 holds promise for polarization-engineered devices but remains hindered by unresolved polarization orientation and ambiguous piezoelectric responses. Here, using an integrated experimental and theoretical approach, we demonstrate that ε-Ga2O3 exhibits a spontaneous polarization (Psp) of −24.8 μC/cm2 oriented antiparallel to the crystal growth direction. The piezoelectric coefficient d33 was experimentally measured as 4.125 pm/V, in strong agreement with the theoretical value of 4.93 pm/V. The phase-pure ε-Ga2O3 films were grown via low-pressure mist-CVD with exceptional crystallinity, as evidenced by an x-ray diffractometer rocking curve [full-width-at-half-maximum (FWHM) = 0.08°]. Optimized piezoelectric force microscopy protocols were employed to determine d33, while the orientation of Psp was resolved using pulsed DC bias-dependent amplitude/phase-voltage measurements combined with aberration-corrected scanning transmission electron microscopy. This multimodal methodology enabled direct mapping of bound charge distributions at the film surface and provided atomic-scale visualization of crystal orientation. These findings clarify ε-Ga2O3 polarization ambiguities, establish structure–property relationships, and unlock transformative potential for advancing power electronics, high-frequency communication systems, and energy-efficient memory technologies.
{"title":"Atomic-level revelation of spontaneous polarization orientation and piezoelectricity in ε -Ga2O3","authors":"Yan Wang, Zhigao Xie, Yizhang Guan, Jiahe Cao, Yibo Zhang, Guofeng Hu, Yu Bai, Yew Hoong Wong, Guosong Zeng, Zhiqiang Huang, Chee Keong Tan","doi":"10.1063/5.0321241","DOIUrl":"https://doi.org/10.1063/5.0321241","url":null,"abstract":"Advancing polarization control in semiconductors is pivotal for next-generation electronics, enabling revolutionary advances in energy and industrial systems. The metastable ε-Ga2O3 holds promise for polarization-engineered devices but remains hindered by unresolved polarization orientation and ambiguous piezoelectric responses. Here, using an integrated experimental and theoretical approach, we demonstrate that ε-Ga2O3 exhibits a spontaneous polarization (Psp) of −24.8 μC/cm2 oriented antiparallel to the crystal growth direction. The piezoelectric coefficient d33 was experimentally measured as 4.125 pm/V, in strong agreement with the theoretical value of 4.93 pm/V. The phase-pure ε-Ga2O3 films were grown via low-pressure mist-CVD with exceptional crystallinity, as evidenced by an x-ray diffractometer rocking curve [full-width-at-half-maximum (FWHM) = 0.08°]. Optimized piezoelectric force microscopy protocols were employed to determine d33, while the orientation of Psp was resolved using pulsed DC bias-dependent amplitude/phase-voltage measurements combined with aberration-corrected scanning transmission electron microscopy. This multimodal methodology enabled direct mapping of bound charge distributions at the film surface and provided atomic-scale visualization of crystal orientation. These findings clarify ε-Ga2O3 polarization ambiguities, establish structure–property relationships, and unlock transformative potential for advancing power electronics, high-frequency communication systems, and energy-efficient memory technologies.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"229 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147524023","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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