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Avalanche and surge robustness involve fundamental carrier dynamics under high electric field and current density. They are also prerequisites of any power device to survive common overvoltage and overcurrent stresses in power electronics applications such as electric vehicles, electricity grids, and renewable energy processing. Despite tremendous efforts to develop the next-generation power devices using emerging ultra-wide bandgap semiconductors, the lack of effective bipolar doping has been a daunting obstacle for achieving the necessary robustness in these devices. Here we report avalanche and surge robustness in a heterojunction formed between the ultra-wide bandgap n-type gallium oxide and the wide-bandgap p-type nickel oxide. Under 1500 V reverse bias, impact ionization initiates in gallium oxide, and the staggered band alignment favors efficient hole removal, enabling a high avalanche current over 50 A. Under forward bias, bipolar conductivity modulation enables the junction to survive over 50 A surge current. Moreover, the asymmetric carrier lifetime makes the high-level carrier injection dominant in nickel oxide, enabling a fast reverse recovery within 15 ns. This heterojunction breaks the fundamental trade-off between robustness and switching speed in conventional homojunctions and removes a key hurdle to advance ultra-wide bandgap semiconductor devices for power industrial applications. Avalanche and surge robustness are fundamental for power devices to survive overvoltage and overcurrent stresses in typical applications. Here, authors report NiO/Ga 2 O 3 heterojunctions with smaller reverse recovery, higher switching speed, and a robustness competitive to that of conventional homojunctions.

Ultra-wide bandgap semiconductors exhibit advantageous electronic properties that make them promising for high-voltage, high-power electronics applications. Building on over a decade of progress in material growth and device fabrication, discrete ultra-wide bandgap devices with power-switching capacities up to the kilowatt level have been recently demonstrated. However, a packaged, multi-die ultra-wide bandgap power module – essential for further power scaling toward industrial, biomedical, grid, and aerospace applications – has yet to be realized. Here, we present a flip-chip packaged gallium oxide power module capable of 1000 A, 1000 V pulsed power switching with fast speed and minimal reverse recovery, advancing the power capacity of ultra-wide bandgap electronics by over two orders of magnitude. To address challenges posed by high electric fields and transient power surges, we employ a high-permittivity interface design enabling device-package electrothermal co-optimization. This optimization maximizes the module’s transient thermal performance and enables full exploitation of the high volumetric heat capacity of gallium oxide—a largely untapped advantage in prior device development—alongside its high-temperature stability. The optimized ultra-wide bandgap module achieves over 1.8 MW/cm 2 pulsed power capacity density, outperforming silicon and wide-bandgap semiconductor counterparts and suggesting the promise of ultra-wide bandgap electronics in next-generation high-power systems. Achieving high power scaling in ultrawide bandgap electronics remains challenging. Here, the authors present a Ga₂O₃ module using a high permittivity interface that enables fast megawatt pulsed switching with improved thermal performance.

Cryogenic electronic circuits are crucial for interfacing and controlling scalable quantum computing platforms at millikelvin temperatures, yet face stringent thermal constraints demanding ultra-low power operation. Neuromorphic circuits, emulating the spiking behavior of biological neurons, offer solution for achieving energy-efficient electronics under these conditions. Here, we report the gate-controlled negative differential resistance (NDR) in silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs). This NDR effect, arising from electron-donor impact ionization (EDII) in SiC MOSFET, achieves on/off current ratio over 10 7 . Meanwhile, the behavior of NDR can be fully controlled by the gate voltage of the MOSFET. Leveraging this gate-controlled NDR, we demonstrate programmable cryogenic spiking neuromorphic circuits, including sensory, logic, and integrate-and-fire neurons, with functionality tuned by gate or drain voltages. The established manufacturability of SiC technology highlights the potential of this approach for scalable integration in cryogenic systems for sensing, computing, and quantum information. Efficient cryogenic electronics are essential for quantum computing at millikelvin temperatures. Yang et al. report a SiC-based negative differential resistance device with high on/off ratio at millikelvin and demonstrate programmable cryogenic neuromorphic circuits including sensory, logic and spiking neurons.

Gallium-nitride high-electron-mobility-transistor is an industrial leading contender for high-frequency and high-power radio-frequency applications. However, the record output-power-density has remained stagnant for nearly two decades, limited by high thermal-resistances at the nucleation layer-substrate interface and thick nitride layers. Here, we propose induced nucleation by implementing ion-implantation on silicon-carbide substrate to create nano- to microscale surface nucleation-sites. This approach suppresses conventional island-like nucleation, enabling rapid film coalescence and aggressive reduction in buffer layer thickness while maintaining low dislocation density. Therefore, a low thermal-resistance of 3.9 m²K/GW for the entire epitaxial stack is achieved, three times lower than previous reports in various high-electron-mobility-transistor epi-structures. Gallium-nitride transistors demonstrate a record Johnson’s Figure-of-Merit of 20.6 THz·V, an output-power-density of 42/20 W/mm at 8/30 GHz, representing a 30%/43% improvement over prior highest output-power-density for all X-/Ka-band transistors, respectively. This result manifests the implantation-induced nucleation strategy as a promising approach for advancing Gallium-nitride heteroepitaxy for RF electronics. Achieving high output-power-density in Gallium-nitride transistors is challenging due to high thermal resistances and thick nitride layers. Here, the authors propose ion-implantation on silicon-carbide substrates, achieving high performance and reduced thermal resistance.

Defect engineering is pivotal in comprehending physical mechanisms that govern carrier transport and device performance. The defect evolution and carrier manipulation in Sn-doped Ga 2 O 3 bulk crystals subjected to different thermal treatments were investigated, utilizing depth-profiled deep-level transient spectroscopy (DLTS) and frequency-dependent capacitance-voltage ( C-V-f ) techniques. In untreated Sn-doped Ga 2 O 3 with an electron concentration of 6.37×10 17 cm −3 , two dominant electron traps, E T1 ( E C −0.68 eV) and E T2 ( E C −0.76 eV), were identified, corresponding to gallium vacancy (V Ga ) and the neutral complex of V Ga -V O , respectively, and characterized as bulk traps. Fe Ga -related defects, E T3 ( E C ∓0.84 eV), were concentrated near surface. Nitrogen annealing significantly reduced E T1 , increased E T2 density from 6.13×10 15 to 1.1×10 16 cm −3 , and raised the interfacial state density ( D it ) to 3.36×10 15 eV −1 cm −2 , accompanied by an elevated electron concentration of 7.48×10 18 cm −3 . In contrast, air annealing enhanced E T1 , with a density of 1.42×10 16 cm −3 , suppressed of E T2 /E T3 traps, resulting in a lower D it of 1.74×10 14 eV −1 cm −2 , and a reduced electron concentration to 3.01×10 16 cm −3 . The findings reveal that a reducing environment induces V O formation and converts discrete V Ga acceptors into neutral V Ga -V O complexes, leading to downward surface band bending and electron accumulation. Conversely, V Ga -V O complexes are dissociated into V Ga acceptors in oxidizing conditions, leading to an upward surface band bending and electron compensation. This work underscores the carrier concentration manipulation by defect engineering in Ga 2 O 3 , offering insights essential for developing high-performance gallium oxide electronics.

Background Tianjin, a major hub in northern China, faces rising HIV-1 infections dominated by CRF01_AE and CRF07_BC. This study elucidated their divergent transmission patterns and drug resistance dynamics to guide targeted interventions. Methods This study included samples identified as CRF01_AE and CRF07_BC subtypes through various methods between 2013 and 2022. BEAST software was used to examine the spatiotemporal transmission patterns of these subtypes in Tianjin. By integrating HIV-TRACE, we constructed high-risk transmission clusters and identified drug resistance mutations (DRMs) based on the Stanford HIV Drug Resistance Database. Finally, the birth–death skyline serial (BDSKY) model was employed to dynamically assess the effective reproductive number (Re) of both subtypes to predict future transmission dynamics. Results CRF01_AE might be introduced in 1988 from Henan and Zhejiang, forming multiple small clusters (< 10 nodes) and spreading through both heterosexual and men who have sex with men (MSM) in Tianjin, while CRF07_BC from Chongqing and Guizhou, et al. in 2004, experiencing explosive local transmission and forming a large cluster of 170 nodes primarily among MSM under 30 years old ( P  < 0.05). Phylogenetic analysis indicated that CRF01_AE has a significantly higher evolutionary rate (2.08 × 10⁻ 3 vs. 1.48 × 10⁻ 3 substitutions/site/year, P  < 0.05), while CRF07_BC demonstrates a greater cluster formation capacity (56.6% vs. 37.1%, P  < 0.05). CRF01_AE showed a higher mutation occurrence rate (5.18% vs. 2.49%, P < 0.05), particularly with non-nucleoside reverse transcriptase inhibitor (NNRTI) associated mutations (e.g., K101E). Although CRF07_BC had a lower resistance burden, the emergence of K103E mutations suggests a need for vigilance regarding potential decreases in sensitivity to newer NNRTIs. BDSKY modeling revealed that the Re for CRF01_AE dropped below 1 after 2016, whereas CRF07_BC’s Re remains above 1, indicating that the risk of transmission still exists. Conclusion Subtype-specific strategies are critical: intensified resistance monitoring for CRF01_AE and cluster-focused interventions for CRF07_BC, particularly among young MSM.

Tianjin, a major hub in northern China, faces rising HIV-1 infections dominated by CRF01_(A)E and CRF07_(B)C. This study elucidated their divergent transmission patterns and drug resistance dynamics to guide targeted interventions. This study included samples identified as CRF01_(A)E and CRF07_(B)C subtypes through various methods between 2013 and 2022. BEAST software was used to examine the spatiotemporal transmission patterns of these subtypes in Tianjin. By integrating HIV-TRACE, we constructed high-risk transmission clusters and identified drug resistance mutations (DRMs) based on the Stanford HIV Drug Resistance Database. Finally, the birth-death skyline serial (BDSKY) model was employed to dynamically assess the effective reproductive number (Re) of both subtypes to predict future transmission dynamics. CRF01_(A)E might be introduced in 1988 from Henan and Zhejiang, forming multiple small clusters (< 10 nodes) and spreading through both heterosexual and men who have sex with men (MSM) in Tianjin, while CRF07_(B)C from Chongqing and Guizhou, et al. in 2004, experiencing explosive local transmission and forming a large cluster of 170 nodes primarily among MSM under 30 years old (P < 0.05). Phylogenetic analysis indicated that CRF01_(A)E has a significantly higher evolutionary rate (2.08 × 10â».sup.3 vs. 1.48 × 10â».sup.3 substitutions/site/year, P < 0.05), while CRF07_(B)C demonstrates a greater cluster formation capacity (56.6% vs. 37.1%, P < 0.05). CRF01_(A)E showed a higher mutation occurrence rate (5.18% vs. 2.49%, P < 0.05), particularly with non-nucleoside reverse transcriptase inhibitor (NNRTI) associated mutations (e.g., K101E). Although CRF07_(B)C had a lower resistance burden, the emergence of K103E mutations suggests a need for vigilance regarding potential decreases in sensitivity to newer NNRTIs. BDSKY modeling revealed that the Re for CRF01_(A)E dropped below 1 after 2016, whereas CRF07_(B)C's Re remains above 1, indicating that the risk of transmission still exists. Subtype-specific strategies are critical: intensified resistance monitoring for CRF01_(A)E and cluster-focused interventions for CRF07_(B)C, particularly among young MSM.

Two light-activated NO donors [RuCl(qn)(Lbpy)(NO)]X with 8-hydroxyquinoline (qn) and 2,2′-bipyridine derivatives (Lbpy) as co-ligands were synthesized (Lbpy1 = 4,4′-dicarboxyl-2,2′-dipyridine, X = Cl− and Lbpy2 = 4,4′-dimethoxycarbonyl-2,2′-dipyridine, X = NO3−), and characterized using ultraviolet–visible (UV-vis) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, nuclear magnetic resonance (1H NMR), elemental analysis and electrospray ionization mass spectrometry (ESI-MS) spectra. The [RuCl(qn)(Lbpy2)(NO)]NO3 complex was crystallized and exhibited distorted octahedral geometry, in which the Ru–N(O) bond length was 1.752(6) Å and the Ru–N–O angle was 177.6(6)°. Time-resolved FT-IR and electron paramagnetic resonance (EPR) spectra were used to confirm the photoactivated NO release of the complexes. The binding constant (Kb) of two complexes with human serum albumin (HSA) and DNA were quantitatively evaluated using fluorescence spectroscopy, Ru-Lbpy1 (Kb~106 with HSA and ~104 with DNA) had higher affinity than Ru-Lbpy2. The interactions between the complexes and HSA were investigated using matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS) and EPR spectra. HSA can be used as a carrier to facilitate the release of NO from the complexes upon photoirradiation. The confocal imaging of photo-induced NO release in living cells was successfully observed with a fluorescent NO probe. Moreover, the photocleavage of pBR322 DNA for the complexes and the effect of different Lbpy substituted groups in the complexes on their reactivity were analyzed.

BackgroundTumor-associated macrophages (TAMs) resemble M2-polarized cells with potent immunosuppressive activity and play a pivotal role in tumor growth and progression. Converting TAMs to proinflammatory M1-like phenotype is thus an attractive strategy for antitumor immunotherapy.MethodsA mouse IgG1 (kappa) monoclonal Ab, M-860, specific to human lactoferrin (LTF) was generated by using the traditional hybridoma cell fusion technology. TAMs were generated by culturing human and mouse CD14+ monocytes in tumor-conditioned media containing a cytokine cocktail containing recombinant interleukin-4 (IL-4), interleukin-10 (IL-10) and macrophage colony stimulating factor (M-CSF). TAMs after treatment with immunocomplex (IC) between human LTF and M860 (LTF-IC) were phenotypically and functionally characterized by flow cytometry (FACS), ELISA, Q-PCR and killing assays. The antitumor effects of LTF-IC were further analyzed using in vivo experiments employing tumor-bearing human FcγRIIa-transgenic mouse models.ResultsThrough coligation of membrane-bound CD14 and FcγRIIa, LTF-IC rendered TAMs not only M2 to M1 conversion, evidenced by increased tumor necrosis factor α production, down-regulated M2-specific markers (CD206, arginase-1 and vascular endothelial growth factor) and upregulated M1-specific markers (CD86 and HLA-DR) expression, but also potent tumoricidal activity in vitro. LTF-IC administration conferred antitumor protective efficacy and prolonged animal survival in FcγRIIa-transgenic mice, accompanied by accumulation of M1-like macrophages as well as significantly reduced infiltration of immunosuppressive myeloid-derived suppressor cells and regulatory T cells in solid tumor tissues.ConclusionsLTF-IC is a promising cancer therapeutic agent capable of converting TAMs into tumoricidal M1-like cells.

Two light-activated NO donors [RuCl(qn)(Lbpy)(NO)]X with 8-hydroxyquinoline (qn) and 2,2'-bipyridine derivatives (Lbpy) as co-ligands were synthesized (Lbpy1 = 4,4'-dicarboxyl-2,2'-dipyridine, X = Cl- and Lbpy2 = 4,4'-dimethoxycarbonyl-2,2'-dipyridine, X = NO3-), and characterized using ultraviolet-visible (UV-vis) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, nuclear magnetic resonance (1H NMR), elemental analysis and electrospray ionization mass spectrometry (ESI-MS) spectra. The [RuCl(qn)(Lbpy2)(NO)]NO3 complex was crystallized and exhibited distorted octahedral geometry, in which the Ru-N(O) bond length was 1.752(6) Å and the Ru-N-O angle was 177.6(6)°. Time-resolved FT-IR and electron paramagnetic resonance (EPR) spectra were used to confirm the photoactivated NO release of the complexes. The binding constant (Kb) of two complexes with human serum albumin (HSA) and DNA were quantitatively evaluated using fluorescence spectroscopy, Ru-Lbpy1 (Kb~106 with HSA and ~104 with DNA) had higher affinity than Ru-Lbpy2. The interactions between the complexes and HSA were investigated using matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS) and EPR spectra. HSA can be used as a carrier to facilitate the release of NO from the complexes upon photoirradiation. The confocal imaging of photo-induced NO release in living cells was successfully observed with a fluorescent NO probe. Moreover, the photocleavage of pBR322 DNA for the complexes and the effect of different Lbpy substituted groups in the complexes on their reactivity were analyzed.Two light-activated NO donors [RuCl(qn)(Lbpy)(NO)]X with 8-hydroxyquinoline (qn) and 2,2'-bipyridine derivatives (Lbpy) as co-ligands were synthesized (Lbpy1 = 4,4'-dicarboxyl-2,2'-dipyridine, X = Cl- and Lbpy2 = 4,4'-dimethoxycarbonyl-2,2'-dipyridine, X = NO3-), and characterized using ultraviolet-visible (UV-vis) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, nuclear magnetic resonance (1H NMR), elemental analysis and electrospray ionization mass spectrometry (ESI-MS) spectra. The [RuCl(qn)(Lbpy2)(NO)]NO3 complex was crystallized and exhibited distorted octahedral geometry, in which the Ru-N(O) bond length was 1.752(6) Å and the Ru-N-O angle was 177.6(6)°. Time-resolved FT-IR and electron paramagnetic resonance (EPR) spectra were used to confirm the photoactivated NO release of the complexes. The binding constant (Kb) of two complexes with human serum albumin (HSA) and DNA were quantitatively evaluated using fluorescence spectroscopy, Ru-Lbpy1 (Kb~106 with HSA and ~104 with DNA) had higher affinity than Ru-Lbpy2. The interactions between the complexes and HSA were investigated using matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS) and EPR spectra. HSA can be used as a carrier to facilitate the release of NO from the complexes upon photoirradiation. The confocal imaging of photo-induced NO release in living cells was successfully observed with a fluorescent NO probe. Moreover, the photocleavage of pBR322 DNA for the complexes and the effect of different Lbpy substituted groups in the complexes on their reactivity were analyzed.