Nan Wu, Jing Lin, Changrong Xie, Zechen Guo, Wenhui Huang, Libo Zhang, Yuxuan Zhou, Xuandong Sun, Jiawei Zhang, Weijie Guo, Xiayu Linpeng, Song Liu, Yang Liu, Wenhui Ren, Ziyu Tao, Ji Jiang, Ji Chu, Jingjing Niu, Youpeng Zhong, Dapeng Yu
Mixers play a crucial role in superconducting quantum computing, primarily by facilitating frequency conversion of signals to enable precise control and readout of quantum states. However, imperfections, particularly local oscillator leakage and unwanted sideband signal, can significantly compromise control fidelity. To mitigate these defects, regular and precise mixer calibrations are indispensable, yet they pose a formidable challenge in large-scale quantum control. Here, we introduce an in situ and scalable mixer calibration scheme using superconducting qubits. Our method leverages the qubit's response to imperfect signals, allowing for calibration without modifying the wiring configuration. We experimentally validate the efficacy of this technique by benchmarking single-qubit gate error and qubit coherence time.
{"title":"In situ mixer calibration for superconducting quantum circuits","authors":"Nan Wu, Jing Lin, Changrong Xie, Zechen Guo, Wenhui Huang, Libo Zhang, Yuxuan Zhou, Xuandong Sun, Jiawei Zhang, Weijie Guo, Xiayu Linpeng, Song Liu, Yang Liu, Wenhui Ren, Ziyu Tao, Ji Jiang, Ji Chu, Jingjing Niu, Youpeng Zhong, Dapeng Yu","doi":"10.1063/5.0234579","DOIUrl":"https://doi.org/10.1063/5.0234579","url":null,"abstract":"Mixers play a crucial role in superconducting quantum computing, primarily by facilitating frequency conversion of signals to enable precise control and readout of quantum states. However, imperfections, particularly local oscillator leakage and unwanted sideband signal, can significantly compromise control fidelity. To mitigate these defects, regular and precise mixer calibrations are indispensable, yet they pose a formidable challenge in large-scale quantum control. Here, we introduce an in situ and scalable mixer calibration scheme using superconducting qubits. Our method leverages the qubit's response to imperfect signals, allowing for calibration without modifying the wiring configuration. We experimentally validate the efficacy of this technique by benchmarking single-qubit gate error and qubit coherence time.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"72 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142609894","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}
Yushen Liu, Bingjie Ye, Yang Gao, Xifeng Yang, Mingfa Peng, Guofeng Yang
All-inorganic perovskites have attracted increasing attention because of their strong environmental stability and excellent photoelectric properties. However, the limited spectral response range of perovskite photodetectors restricts them in practical applications. In this work, an ultraviolet–visible photodetector with a wide spectral response and a high responsivity was prepared by constructing a CsPbBr3 quantum dots (QDs)/p-GaN heterojunction. The type-II energy band alignment formed by the heterojunction is conducive to the transport of photogenerated carriers, resulting in a high responsivity. Under certain conditions, the device can obtain responsivity values of 5 A/W and 850 mA/W under 350 and 725 nm illumination, respectively, which are comparable to those of other perovskite-based photodetectors. In addition, the photoresponse mechanism of the device is revealed through first-principles calculations of the heterojunction and the device. The enhanced light absorption of the heterojunction and the special band bending under different bias voltages improve the photoelectric performance of the device. This work can provide valuable insights into high-performance photodetectors based on all-inorganic perovskite QDs heterojunctions in terms of band regulation and device performance improvement.
{"title":"CsPbBr3 perovskite quantum dots/p-GaN heterojunction for ultraviolet-visible spectrum photodetectors","authors":"Yushen Liu, Bingjie Ye, Yang Gao, Xifeng Yang, Mingfa Peng, Guofeng Yang","doi":"10.1063/5.0238223","DOIUrl":"https://doi.org/10.1063/5.0238223","url":null,"abstract":"All-inorganic perovskites have attracted increasing attention because of their strong environmental stability and excellent photoelectric properties. However, the limited spectral response range of perovskite photodetectors restricts them in practical applications. In this work, an ultraviolet–visible photodetector with a wide spectral response and a high responsivity was prepared by constructing a CsPbBr3 quantum dots (QDs)/p-GaN heterojunction. The type-II energy band alignment formed by the heterojunction is conducive to the transport of photogenerated carriers, resulting in a high responsivity. Under certain conditions, the device can obtain responsivity values of 5 A/W and 850 mA/W under 350 and 725 nm illumination, respectively, which are comparable to those of other perovskite-based photodetectors. In addition, the photoresponse mechanism of the device is revealed through first-principles calculations of the heterojunction and the device. The enhanced light absorption of the heterojunction and the special band bending under different bias voltages improve the photoelectric performance of the device. This work can provide valuable insights into high-performance photodetectors based on all-inorganic perovskite QDs heterojunctions in terms of band regulation and device performance improvement.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"98 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142609896","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}
Dhanu Chettri, Ganesh Mainali, Juan Huerta Salcedo, Mritunjay Kumar, Vishal Khandelwal, Saravanan Yuvaraja, Xiaohang Li
In this work, we report on the beta-gallium oxide (β-Ga2O3) monolithic bidirectional switch. The as-fabricated switch works on enhancement mode operation with a threshold voltage of ∼4 V. Maximum drain current density of 1.93 mA/mm is obtained with a drain voltage of 5 V. The bidirectional switch in a bidirectional mode has an ON/OFF current ratio of ∼107 with ON-resistance of 1.11 and 1.09 kΩ · mm in forward and reverse direction, respectively. However, in diode mode, the device shows an ON/OFF current ratio of 1.6 × 108 and 1.4 × 108 in forward and reverse conduction modes, respectively. The fabricated β-Ga2O3 monolithic bidirectional switch is then used to chop a 60 Hz Alternating Current signal at a chopping frequency of 1 kHz, indicating its potential applications in a range of converters.
{"title":"Demonstration of normally OFF beta-gallium oxide monolithic bidirectional switch for AC switching applications","authors":"Dhanu Chettri, Ganesh Mainali, Juan Huerta Salcedo, Mritunjay Kumar, Vishal Khandelwal, Saravanan Yuvaraja, Xiaohang Li","doi":"10.1063/5.0237484","DOIUrl":"https://doi.org/10.1063/5.0237484","url":null,"abstract":"In this work, we report on the beta-gallium oxide (β-Ga2O3) monolithic bidirectional switch. The as-fabricated switch works on enhancement mode operation with a threshold voltage of ∼4 V. Maximum drain current density of 1.93 mA/mm is obtained with a drain voltage of 5 V. The bidirectional switch in a bidirectional mode has an ON/OFF current ratio of ∼107 with ON-resistance of 1.11 and 1.09 kΩ · mm in forward and reverse direction, respectively. However, in diode mode, the device shows an ON/OFF current ratio of 1.6 × 108 and 1.4 × 108 in forward and reverse conduction modes, respectively. The fabricated β-Ga2O3 monolithic bidirectional switch is then used to chop a 60 Hz Alternating Current signal at a chopping frequency of 1 kHz, indicating its potential applications in a range of converters.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"72 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142609904","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}
Atmospheric pressure nonequilibrium plasma holds significant potential in biomedical applications due to its ability to generate reactive species at low temperatures. However, accurately quantifying and controlling plasma dosage remains challenging. Although equivalent total oxidation potential (ETOP) has been proposed for defining dosage, previous methods required measurement of various reactive oxygen and nitrogen species (RONS) densities, which are impractical in diverse plasma settings. Efficient ETOP prediction across variable conditions is thus essential. To address this, we propose a machine learning-based ETOP modeling method. This study collected RONS density data under various conditions using laser-induced fluorescence and trained an artificial neural network to predict ETOP values based on input parameters like voltage, gas flow rate, oxygen concentration, and humidity. This approach enables efficient ETOP prediction across variable conditions, supporting the standardization and clinical application of plasma medicine.
{"title":"Determining plasma dose using equivalent total oxidation potential (ETOP): Concept to practical application via machine learning","authors":"E. Wu, K. Song, X. Pei, L. Nie, D. Liu, X. Lu","doi":"10.1063/5.0228789","DOIUrl":"https://doi.org/10.1063/5.0228789","url":null,"abstract":"Atmospheric pressure nonequilibrium plasma holds significant potential in biomedical applications due to its ability to generate reactive species at low temperatures. However, accurately quantifying and controlling plasma dosage remains challenging. Although equivalent total oxidation potential (ETOP) has been proposed for defining dosage, previous methods required measurement of various reactive oxygen and nitrogen species (RONS) densities, which are impractical in diverse plasma settings. Efficient ETOP prediction across variable conditions is thus essential. To address this, we propose a machine learning-based ETOP modeling method. This study collected RONS density data under various conditions using laser-induced fluorescence and trained an artificial neural network to predict ETOP values based on input parameters like voltage, gas flow rate, oxygen concentration, and humidity. This approach enables efficient ETOP prediction across variable conditions, supporting the standardization and clinical application of plasma medicine.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"11 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142609893","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}
For the past few decades, structured light has been gaining popularity across various research fields. Its fascinating properties have been exploited for both previously unforeseen and established applications from new perspectives. Crucial to this is the several techniques that have been proposed for both their generation and characterization. On the one hand, the former has been boosted by the invention of computer-controlled devices, which combined with a few optical components allow flexible and complete control of the spatial and polarization degrees of freedom on light, thus enabling a plethora of proof-of-principle experiments for novel and old applications. On the other hand, characterizing light beams is important not only for gaining better insights into light's properties but also for potentially being used as metrics. In this perspective, we thus offer our take on a few key applied research fields where structured light is particularly promising, as well as some pivotal generation and characterization techniques. In addition, we share our vision of where we believe structured light's applications are moving toward.
{"title":"A perspective on structured light's applications","authors":"Carmelo Rosales-Guzmán, Valeria Rodríguez-Fajardo","doi":"10.1063/5.0236477","DOIUrl":"https://doi.org/10.1063/5.0236477","url":null,"abstract":"For the past few decades, structured light has been gaining popularity across various research fields. Its fascinating properties have been exploited for both previously unforeseen and established applications from new perspectives. Crucial to this is the several techniques that have been proposed for both their generation and characterization. On the one hand, the former has been boosted by the invention of computer-controlled devices, which combined with a few optical components allow flexible and complete control of the spatial and polarization degrees of freedom on light, thus enabling a plethora of proof-of-principle experiments for novel and old applications. On the other hand, characterizing light beams is important not only for gaining better insights into light's properties but also for potentially being used as metrics. In this perspective, we thus offer our take on a few key applied research fields where structured light is particularly promising, as well as some pivotal generation and characterization techniques. In addition, we share our vision of where we believe structured light's applications are moving toward.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"23 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142609942","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}
In this Letter, a high-quality and high-resistivity nitrogen (N)-doped Ga2O3 current blocking layer (CBL) is grown utilizing metal-organic chemical vapor deposition homoepitaxial technology. By using nitrous oxide (N2O) as oxygen source for Ga2O3 growth and N source for doping and controlling the growth temperature, the grown CBL can effectively achieve high (∼1019 cm−3) or low (∼1017 cm−3) N doping concentrations, as well as high crystal quality. Furthermore, the electrical properties of the developed CBL are verified at the device level, which shows that the device using the CBL can withstand bidirectional voltages exceeding 3.5 kV with very low leakage (≤1 × 10−4 A/cm2). This work can pave the way for the realization of high-voltage and low-leakage Ga2O3 vertical devices, especially metal-oxide-semiconductor field effect transistors.
{"title":"Nitrogen-doped Ga2O3 current blocking layer using MOCVD homoepitaxy for high-voltage and low-leakage Ga2O3 vertical device fabrication","authors":"Xiaorui Xu, Desen Chen, Yaoping Lu, Titao Li, Xueli Han, Duanyang Chen, Hongji Qi, Dan Yang, Minmin Zhu, Haizhong Zhang, Xiaoqiang Lu","doi":"10.1063/5.0239622","DOIUrl":"https://doi.org/10.1063/5.0239622","url":null,"abstract":"In this Letter, a high-quality and high-resistivity nitrogen (N)-doped Ga2O3 current blocking layer (CBL) is grown utilizing metal-organic chemical vapor deposition homoepitaxial technology. By using nitrous oxide (N2O) as oxygen source for Ga2O3 growth and N source for doping and controlling the growth temperature, the grown CBL can effectively achieve high (∼1019 cm−3) or low (∼1017 cm−3) N doping concentrations, as well as high crystal quality. Furthermore, the electrical properties of the developed CBL are verified at the device level, which shows that the device using the CBL can withstand bidirectional voltages exceeding 3.5 kV with very low leakage (≤1 × 10−4 A/cm2). This work can pave the way for the realization of high-voltage and low-leakage Ga2O3 vertical devices, especially metal-oxide-semiconductor field effect transistors.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"127 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142609895","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}
Xiaodong Qiu, Zhixiong Xiao, Fan Yu, Yuling Yin, Lin Huang, Bin Yang, Qichao Tian, Kaili Wang, Yuyang Mu, Qinghao Meng, Xiangang Wan, Junming Liu, Di Wu, Yi Zhang
The rare-earth Eu-based compounds with a unique half-filled 4f orbital have attracted an amount of research interest recently. Here, we synthesized EuTe(001) single-crystal thin films on SrTiO3(001) substrate via molecular beam epitaxy (MBE). The scanning tunneling microscopy and x-ray diffraction results indicate that the grown EuTe thin films orientated as EuTe[100]//SrTiO3[110] in plane. In the angle-resolved photoemission spectroscopic (ARPES) measurements, the grown EuTe films show a semiconductive band structure with the valence band maximum lying on the center point of the Brillouin zone. The bandgap size of EuTe was further identified by the optical transmission spectra as 2.2 eV. The antiferromagnetic transition temperature of the grown EuTe film is 10.5 K measured by a superconductive quantum interference device (SQUID). Our results provide important information on the fundamental electronic structures for the further research and applications of the Eu-based compounds.
具有独特的半填充 4f 轨道的稀土 Eu 基化合物最近引起了大量研究兴趣。在此，我们通过分子束外延（MBE）技术在 SrTiO3（001）基底上合成了 EuTe（001）单晶薄膜。扫描隧道显微镜和 X 射线衍射结果表明，生长的 EuTe 薄膜在平面上取向为 EuTe[100]//SrTiO3[110]。在角度分辨光发射光谱（ARPES）测量中，生长出的 EuTe 薄膜呈现出价带最大值位于布里渊区中心点的半导体带结构。光透射光谱进一步确定了 EuTe 的带隙大小为 2.2 eV。通过超导量子干涉装置（SQUID）测量，生长的 EuTe 薄膜的反铁磁转变温度为 10.5 K。我们的研究结果为进一步研究和应用 Eu 基化合物提供了重要的基本电子结构信息。
{"title":"Molecular beam epitaxy and band structures of type-II antiferromagnetic semiconductor EuTe thin films","authors":"Xiaodong Qiu, Zhixiong Xiao, Fan Yu, Yuling Yin, Lin Huang, Bin Yang, Qichao Tian, Kaili Wang, Yuyang Mu, Qinghao Meng, Xiangang Wan, Junming Liu, Di Wu, Yi Zhang","doi":"10.1063/5.0227254","DOIUrl":"https://doi.org/10.1063/5.0227254","url":null,"abstract":"The rare-earth Eu-based compounds with a unique half-filled 4f orbital have attracted an amount of research interest recently. Here, we synthesized EuTe(001) single-crystal thin films on SrTiO3(001) substrate via molecular beam epitaxy (MBE). The scanning tunneling microscopy and x-ray diffraction results indicate that the grown EuTe thin films orientated as EuTe[100]//SrTiO3[110] in plane. In the angle-resolved photoemission spectroscopic (ARPES) measurements, the grown EuTe films show a semiconductive band structure with the valence band maximum lying on the center point of the Brillouin zone. The bandgap size of EuTe was further identified by the optical transmission spectra as 2.2 eV. The antiferromagnetic transition temperature of the grown EuTe film is 10.5 K measured by a superconductive quantum interference device (SQUID). Our results provide important information on the fundamental electronic structures for the further research and applications of the Eu-based compounds.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"45 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142601226","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}
Joseph P. Briggs, Yinan Liu, P. Craig Taylor, Meenakshi Singh, Reuben T. Collins, Carolyn A. Koh
Type II Si clathrate is a Si-based, crystalline alternative to diamond silicon with interesting optoelectronic properties. Here, a pulsed electron paramagnetic resonance study of the spin dynamics of sodium-doped, type II NaxSi136 silicon clathrate films is reported. Focusing on the hyperfine lines of isolated Na atoms, the temperature dependence of the electron spin dynamics is examined from 6 to 25 K. The measurements exhibit multi-exponential decay, indicating multiple spin relaxation rates in the system. As expected, spin relaxation time (T1) increases rapidly with decreasing temperature, reaching ∼300 μs at 6.4 K. The phase memory (TM) shows less temperature dependence with a value of ∼3 μs at the same temperature. The temperature dependence of T1 exhibits Arrhenius behavior in the measurement range consistent with an Orbach pathway. There are strong similarities to the spin behavior of other defect donors in diamond silicon. The results provide insights into the potential of Si clathrates for spin-based applications.
二型硅凝胶是一种硅基晶体，可替代金刚石硅，具有有趣的光电特性。本文报告了对掺钠的 II 型 NaxSi136 硅克拉斯薄膜自旋动力学的脉冲电子顺磁共振研究。测量结果呈现多指数衰减，表明系统中存在多种自旋弛豫速率。正如预期的那样，自旋弛豫时间（T1）随着温度的降低而迅速增加，在 6.4 K 时达到 ∼300 μs。在测量范围内，T1 的温度依赖性表现出与奥尔巴赫途径一致的阿伦尼乌斯行为。这与金刚石硅中其他缺陷供体的自旋行为非常相似。这些结果让我们深入了解了硅克拉层在自旋应用方面的潜力。
{"title":"Characterization of low sodium type II silicon clathrate film spin dynamics","authors":"Joseph P. Briggs, Yinan Liu, P. Craig Taylor, Meenakshi Singh, Reuben T. Collins, Carolyn A. Koh","doi":"10.1063/5.0230407","DOIUrl":"https://doi.org/10.1063/5.0230407","url":null,"abstract":"Type II Si clathrate is a Si-based, crystalline alternative to diamond silicon with interesting optoelectronic properties. Here, a pulsed electron paramagnetic resonance study of the spin dynamics of sodium-doped, type II NaxSi136 silicon clathrate films is reported. Focusing on the hyperfine lines of isolated Na atoms, the temperature dependence of the electron spin dynamics is examined from 6 to 25 K. The measurements exhibit multi-exponential decay, indicating multiple spin relaxation rates in the system. As expected, spin relaxation time (T1) increases rapidly with decreasing temperature, reaching ∼300 μs at 6.4 K. The phase memory (TM) shows less temperature dependence with a value of ∼3 μs at the same temperature. The temperature dependence of T1 exhibits Arrhenius behavior in the measurement range consistent with an Orbach pathway. There are strong similarities to the spin behavior of other defect donors in diamond silicon. The results provide insights into the potential of Si clathrates for spin-based applications.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"11 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142609956","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}
In this study, we demonstrate the effects of electron velocity modulation (Δve/ΔVgs) on the microwave power performance for AlGaN/GaN HFETs. In order to conduct the experiments, AlGaN/GaN HFETs with gate lengths ranging from 500 to 80 nm were fabricated. Electron transport was investigated by coupling a drift-diffusion solver with the Monte Carlo method. As gate lengths (Lg) varied from 500 to 200 nm, the increased polarization Coulomb field scattering led to an increase in Δve/ΔVgs and the stronger electric field (E) increased ve and enhanced the transconductance (gm), which in turn led to a greater power gain (Gp) in the HFETs. The higher power output (Pout) was also due to the increased ve that boosted the saturated output current (Ids,sat). The unique phenomenon that occurs from electron velocity modulation of AlGaN/GaN HFETs at electron densities (ns) < 3.42 × 1012cm−2 can be used as an effective mechanism to enhance the power gain of AlGaN/GaN HFETs.
{"title":"Impact of electron velocity modulation on microwave power performance for AlGaN/GaN HFETs","authors":"Mingyan Wang, Yuanjie Lv, Heng Zhou, Chao Liu, Peng Cui, Zhaojun Lin","doi":"10.1063/5.0222095","DOIUrl":"https://doi.org/10.1063/5.0222095","url":null,"abstract":"In this study, we demonstrate the effects of electron velocity modulation (Δve/ΔVgs) on the microwave power performance for AlGaN/GaN HFETs. In order to conduct the experiments, AlGaN/GaN HFETs with gate lengths ranging from 500 to 80 nm were fabricated. Electron transport was investigated by coupling a drift-diffusion solver with the Monte Carlo method. As gate lengths (Lg) varied from 500 to 200 nm, the increased polarization Coulomb field scattering led to an increase in Δve/ΔVgs and the stronger electric field (E) increased ve and enhanced the transconductance (gm), which in turn led to a greater power gain (Gp) in the HFETs. The higher power output (Pout) was also due to the increased ve that boosted the saturated output current (Ids,sat). The unique phenomenon that occurs from electron velocity modulation of AlGaN/GaN HFETs at electron densities (ns) &lt; 3.42 × 1012cm−2 can be used as an effective mechanism to enhance the power gain of AlGaN/GaN HFETs.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"11 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142601220","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 unique spin-optical properties of NV defects in SiC, coupled with silicon carbide's advanced technology compared to diamond, make them a promising candidate for quantum technology applications. In this study, using photoinduced pulse ESR at 94 GHz (3.4 T), we reveal the room temperature spin coherence of NV defects in 6H-28SiC, purified to reduce 29Si concentration to ≈1%, four times below its natural level. We demonstrate room temperature (300 K) Hahn-echo coherence time T2 = 23.6 μs, spin–lattice relaxation time T1 = 0.1 ms, and coherent control over optically polarized NV spin states through Rabi nutation experiments. We reveal long inhomogeneous dephasing time T2* = 1.5 μs, which is about five times greater than that measured for NV defects in SiC with natural isotopic content. Our observations highlight again the potential of NV defects in 6H-28SiC, which exhibit near-infrared optical excitation and emission properties compatible with O-band fiber optics, as promising candidates for applications in quantum sensing, communication, and computation.
{"title":"Coherence of NV defects in isotopically enriched 6H-28SiC at ambient conditions","authors":"Fadis Murzakhanov, Georgy Mamin, Margarita Sadovnikova, Evgeniy Mokhov, Sergey Nagalyuk, Marat Gafurov, Victor Soltamov","doi":"10.1063/5.0222098","DOIUrl":"https://doi.org/10.1063/5.0222098","url":null,"abstract":"The unique spin-optical properties of NV defects in SiC, coupled with silicon carbide's advanced technology compared to diamond, make them a promising candidate for quantum technology applications. In this study, using photoinduced pulse ESR at 94 GHz (3.4 T), we reveal the room temperature spin coherence of NV defects in 6H-28SiC, purified to reduce 29Si concentration to ≈1%, four times below its natural level. We demonstrate room temperature (300 K) Hahn-echo coherence time T2 = 23.6 μs, spin–lattice relaxation time T1 = 0.1 ms, and coherent control over optically polarized NV spin states through Rabi nutation experiments. We reveal long inhomogeneous dephasing time T2* = 1.5 μs, which is about five times greater than that measured for NV defects in SiC with natural isotopic content. Our observations highlight again the potential of NV defects in 6H-28SiC, which exhibit near-infrared optical excitation and emission properties compatible with O-band fiber optics, as promising candidates for applications in quantum sensing, communication, and computation.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"152 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142601223","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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