Applied Physics Letters最新文献_第5页

Integration of top-side low-temperature diamond on AlGaN/GaN RF HEMT for device-level cooling 在AlGaN/GaN射频HEMT上集成顶部低温金刚石，用于器件级冷却

IF 4 2区物理与天体物理

Applied Physics Letters Pub Date : 2025-05-27 DOI: 10.1063/5.0261673

Rohith Soman, Mohamadali Malakoutian, Kelly Woo, Jeong-Kyu Kim, Thomas Andres Rodriguez, Rafael Perez Martinez, Matthew DeJarld, Maher Tahhan, Jarrod Valliancourt, Eduardo M. Chumbes, Jeffrey Laroche, Srabanti Chowdhury

{"title":"Integration of top-side low-temperature diamond on AlGaN/GaN RF HEMT for device-level cooling","authors":"Rohith Soman, Mohamadali Malakoutian, Kelly Woo, Jeong-Kyu Kim, Thomas Andres Rodriguez, Rafael Perez Martinez, Matthew DeJarld, Maher Tahhan, Jarrod Valliancourt, Eduardo M. Chumbes, Jeffrey Laroche, Srabanti Chowdhury","doi":"10.1063/5.0261673","DOIUrl":"https://doi.org/10.1063/5.0261673","url":null,"abstract":"Self-heating and related degradation in performance and reliability are serious concerns in realizing higher output power density in microwave power amplifiers. We demonstrated the integration of polycrystalline diamond on a fully fabricated metal-polar Schottky-gated AlGaN/GaN microwave transistor for the device-level cooling solution. The thermal budget of the diamond integration process is carefully optimized so as not to degrade the electrical performance of the device. Gate resistance thermometry measurement performed on a 1 × 200 μm2 device showed an average 111 °C lower channel temperature from 488 °C for the devices with diamond at 24 W/mm power dissipation than those without diamond. The gate leakage current of the device increased only by 4.8 times with the optimized diamond growth process. An extrinsic Ft/Fmax of 23/33 GHz was measured on devices with diamond compared to 23/36 GHz on devices without diamond. Diamond integration and gate leakage current modeling were also discussed on a 10-finger HEMT.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"69 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144154132","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}

引用次数: 0

A logic metastructure for register function implementation 寄存器函数实现的逻辑元结构

IF 4 2区物理与天体物理

Applied Physics Letters Pub Date : 2025-05-27 DOI: 10.1063/5.0265284

Jia-Hao Zou, Jun-Yang Sui, Hai-Feng Zhang

{"title":"A logic metastructure for register function implementation","authors":"Jia-Hao Zou, Jun-Yang Sui, Hai-Feng Zhang","doi":"10.1063/5.0265284","DOIUrl":"https://doi.org/10.1063/5.0265284","url":null,"abstract":"A coherent perfect absorption-based logic metastructure (LM) capable of register functionality is presented in the work. The unique one-dimensional layered architecture enables dual electromagnetic wave selectivity in both frequency and spatial angle domains within specific spectral ranges. The structure contains graphene layers as the tunable dielectric for the LM. By controlling the chemical potential of graphene, the incidence angle, and the phase difference of the coherent light, the coherent absorptivity of the LM can be changed accordingly. By establishing logic-level definitions for input/output signals, two distinct operational conditions that define logical relationships between inputs and outputs are derived. Under these dual operational modes, the LM achieves data registration across eight discrete addresses. The system employs clock signal synchronization to correlate outputs from both states with one serving as a block register that identifies the data block location and the other functioning as a data register outputting actual content. The combined output from both registers generates the complete physical address of stored data. This architectural design enables simultaneous 128-bit data registration (8 × 2 × 8), demonstrating the potential for high-density optical information processing applications.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"43 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144153878","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}

引用次数: 0

Background-free microwave-induced thermoacoustic imaging by magnetic field modulation 磁场调制的无背景微波热声成像

IF 4 2区物理与天体物理

Applied Physics Letters Pub Date : 2025-05-27 DOI: 10.1063/5.0271610

Guojia Huang, Yu Wang, Shanxiang Zhang, Famin Huang, Huan Qin

引用次数: 0

Robust and tunable oxide nanoscrolls for solar-driven H2 generation and storage 用于太阳能驱动的氢气生成和储存的坚固可调氧化物纳米卷

IF 4 2区物理与天体物理

Applied Physics Letters Pub Date : 2025-05-27 DOI: 10.1063/5.0268315

Adway Gupta, Arunima K. Singh

{"title":"Robust and tunable oxide nanoscrolls for solar-driven H2 generation and storage","authors":"Adway Gupta, Arunima K. Singh","doi":"10.1063/5.0268315","DOIUrl":"https://doi.org/10.1063/5.0268315","url":null,"abstract":"Hydrogen gas is a promising alternative to fossil fuels due to its high energy output and environmentally safe byproducts. Various morphologies of photocatalytic materials have been explored for high-efficiency H2 production, for instance, quasi-1D nanoscroll structures that provide a larger surface-to-volume ratio. Recently, we predicted layer-by-layer formation of stable oxide nanoscrolls directly from dichalcogenide precursors, eliminating the need for costly formation of two-dimensional oxides for a roll-up synthesis of nanoscrolls. In this study, we evaluate the suitability of those oxide nanoscroll materials—MoO3, WO3, PdO2, HfO2, and GeO2—for solar-driven photocatalytic H2 production and storage. Using excited state theory coupled with Bethe–Salpeter equation simulations, we discern their electronic and optical properties as a function of interlayer scroll spacing and find them to be highly conducive for solar-driven photocatalysis. Additionally, using ab initio molecular dynamics simulations, we show that they are also suitable for H2 storage as the nanoscrolls exhibit an effective trapping of hydrogen, even in the presence of defects and vacancies in the oxides. This work thus demonstrates the discovery of robust and tunable oxide nanoscrolls as materials for advancing solar-driven hydrogen technologies.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"33 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144154138","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}

引用次数: 0

AlN-based polarization-doped field-effect transistors with downward-graded AlGaN underlayers 具有向下梯度AlGaN衬底的aln极化掺杂场效应晶体管

IF 4 2区物理与天体物理

Applied Physics Letters Pub Date : 2025-05-23 DOI: 10.1063/5.0268213

Masanobu Hiroki, Kazuyuki Hirama, Kazuhide Kumakura, Yoshitaka Taniyasu

{"title":"AlN-based polarization-doped field-effect transistors with downward-graded AlGaN underlayers","authors":"Masanobu Hiroki, Kazuyuki Hirama, Kazuhide Kumakura, Yoshitaka Taniyasu","doi":"10.1063/5.0268213","DOIUrl":"https://doi.org/10.1063/5.0268213","url":null,"abstract":"We propose AlN-based polarization-doped field-effect transistors (PolFETs) with upward-graded AlxGa1−xN channel layers combined with downward-graded AlGaN underlayers (ULs). In a structure where the channel layer is directly formed on an AlN buffer layer without a UL, the large polarization charge of the AlN buffer layer depletes the bottom side of the channel layer, resulting in narrow width of three-dimensional electron gas (3DEG) and high resistance in electrical characterization. In contrast, the structures incorporating ULs exhibit wide 3DEG by leveraging polarization engineering. Hall-effect measurements revealed a sheet electron concentration (nsh) of 6.2×1012 cm−2 and electron mobility (μ) of 187 cm2 V−1 s−1 for a 100-nm-thick upward-graded AlxGa1−xN (x:0.77→1) with an undoped 300-nm-thick downward-graded AlyGa1−yN (y:1→0.77) UL. Silicon doping in the UL compensates for their negative polarization charge, further increasing nsh to 7.2×1012 cm−2 while maintaining μ of 200 cm2 V−1 s−1 at a Si doping concentration of 3.3×1017 cm−3. The PolFET with the Si-doped UL exhibits a drain current of 70 mA/mm. The off-state leakage current is as low as 4×10−10 A/mm, leading to large on/off ratio of 108. Thus, the incorporation of downward-graded AlGaN ULs with Si doping concentrations comparable with the negative polarization charge density in the ULs can boost the performance of AlN-based PolFETs.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"75 9 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144130264","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}

引用次数: 0

Utilization of silicon optical coatings for transverse-mode suppression in high-power oxide-confined vertical-cavity surface-emitting lasers 硅光学涂层在高功率氧化约束垂直腔面发射激光器中横向模抑制的应用

IF 4 2区物理与天体物理

Applied Physics Letters Pub Date : 2025-05-23 DOI: 10.1063/5.0260091

Kevin P. Pikul, Patrick Su, Mark D. Kraman, Benjamin A. Kesler, John M. Dallesasse

{"title":"Utilization of silicon optical coatings for transverse-mode suppression in high-power oxide-confined vertical-cavity surface-emitting lasers","authors":"Kevin P. Pikul, Patrick Su, Mark D. Kraman, Benjamin A. Kesler, John M. Dallesasse","doi":"10.1063/5.0260091","DOIUrl":"https://doi.org/10.1063/5.0260091","url":null,"abstract":"Engineering of the electric-field standing-wave pattern of oxide-confined vertical-cavity surface-emitting lasers (VCSELs) via a scalable, high-refractive-index silicon optical coating is demonstrated to achieve high-power, single-transverse-mode emission. The electron-beam deposition of a thin silicon film atop a standard VCSEL structure reduces the amplitude of the electric-field standing wave over the quantum well gain region, raising the threshold modal gain. Patterning the coating into the shape of an annulus increases the threshold modal gain in the periphery of the VCSEL aperture overlapping with the higher-order transverse modes while leaving the central region unaffected. This patterning creates a radially dependent threshold modal gain profile, suppressing higher-order modes and encouraging operation in a single-fundamental mode. High-power continuous-wave single-mode emission with an output power of 7.43 mW in 850 nm AlGaAs-based VCSELs with silicon coatings is demonstrated, as well as submillamp threshold currents, thermal rollover delay, and a side-mode suppression ratio exceeding 30 dB for single-fundamental-mode operation at room temperature.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"45 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144130265","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}

引用次数: 0

Kinetics of short-range order formation in GeSn alloy: MBE vs CVD GeSn合金的短程有序形成动力学：MBE vs CVD

IF 4 2区物理与天体物理

Applied Physics Letters Pub Date : 2025-05-23 DOI: 10.1063/5.0270281

Yunfan Liang, Damien West, Shengbai Zhang

引用次数: 0

Atomistic insight into enhanced ionic conductivity in mixed halide sodium ion conductor Na3YClxBr6−x 混合卤化钠离子导体Na3YClxBr6−x中离子电导率增强的原子性洞察

IF 4 2区物理与天体物理

Applied Physics Letters Pub Date : 2025-05-22 DOI: 10.1063/5.0257157

Tae-Il Ri, Kum-Chol Ri, Il-Jin Kim, Ju-Ryong Hwang, Chol-Jun Yu

引用次数: 0

Annealing effects on crystalline quality and device performance of ultrawide bandgap h-BN quasi-bulk crystals 退火对超宽带隙h-BN准块体晶体晶体质量和器件性能的影响

IF 4 2区物理与天体物理

Applied Physics Letters Pub Date : 2025-05-22 DOI: 10.1063/5.0260647

N. K. Hossain, G. Somasundaram, Z. Alemoush, J. Li, J. Y. Lin, H. X. Jiang

{"title":"Annealing effects on crystalline quality and device performance of ultrawide bandgap h-BN quasi-bulk crystals","authors":"N. K. Hossain, G. Somasundaram, Z. Alemoush, J. Li, J. Y. Lin, H. X. Jiang","doi":"10.1063/5.0260647","DOIUrl":"https://doi.org/10.1063/5.0260647","url":null,"abstract":"Hexagonal boron nitride (h-BN) is a notable member of ultrawide bandgap semiconductors, distinguished by its unique layered crystalline structure and exceptional electrical and optical properties. One of the established and important device applications of h-BN lies in solid-state neutron detectors. Achieving high detection efficiency requires thick, high-quality crystals to maximize neutron interactions and charge carrier collection. While hydride vapor phase epitaxy (HVPE) excels at growing thick, uniform h-BN films (quasi-bulk wafers), its high growth rate can compromise crystallinity by introducing structural defects. This study investigates the impact of post-growth high-temperature annealing (up to 1900 °C) on 1 mm thick HVPE-grown h-BN. X-ray diffraction confirmed significant improvements in crystallinity with higher annealing temperatures, leading to increased resistivity and an enhanced charge carrier mobility-lifetime product. A detector fabricated from h-BN annealed at 1900 °C demonstrated a 0.7% overall detection efficiency and 37% charge collection efficiency for fast neutrons from an AmBe source. These findings highlight post-growth annealing as a simple yet highly effective method to improve h-BN quality for a wide range of applications, including direct conversion solid-state neutron detectors, which are becoming increasingly vital in various nuclear diagnostic instruments.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"144 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144122490","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}

引用次数: 0

Optomechanical thermal effect of nanofilm by time-correlated single-photon counting 用时间相关单光子计数研究纳米膜的光力学热效应

IF 4 2区物理与天体物理

Applied Physics Letters Pub Date : 2025-05-22 DOI: 10.1063/5.0257450

Hui Wu, Guangyu Li, Zhe He

引用次数: 0