Abstract In this study, we first inversely derive the required Willis parameters for realizing extreme contrast of scattering waves in opposite direction. Then, we propose an active acoustic metastructure to achieve nonreciprocal Willis coupling and experimentally realize the strong transmission and reflection simultaneously in one direction while exhibiting absorption in the opposite direction. Without prior knowledge of the incident field, the working frequency of the metastructure can be self-adjusted in real time. The proposed active nonreciprocal Willis metastructure provides an avenue on unsurpassed control of sound transport.

Abstract Nonthermal plasma coupled with H2O2 and HBO3 treatment was examined to enhance cellulose flame resistance (FR) through the plasma-liquid interaction (PLI) of the H2O2 solution (indirect method) and plasma-activated surface (PAS) by Ar plasma jet (direct method). Here, the results revealed a significant increase in cellulose FR of up to 48% with plasma treatments, depending on flame exposure time and synthesized procedures. This enhancement is attributed to the changes in the chemical compositions and cellulose surface by plasma treatment, improving boron distribution on the cellulose surface during HBO3 treatment. Compared to the PLI, PAS demonstrated superiority in increasing FR and offered greater economic efficiency by a short treatment time of 1 min.

Abstract Synthesized spin-orbit coupling (SSOC) is crucial for the operation of spin qubits in silicon quantum dot, as it address the challenge posed by the inherently weak intrinsic spin-orbit coupling (ISOC) in silicon. Here, we investigate the anisotropic properties of single spin qubit in silicon metal-oxide-semiconductor (Si-MOS) quantum dot and provide experimental evidence for the control of SSOC. Additionally, we experimentally demonstrate that tuning the operating point away from the conventional configuration can enhance the quality factor of the spin qubit. These findings lay a foundation for the realization of high-quality tunable spin-orbit qubits.

Abstract We report the experimental observation of a spin-polarised conductance plateau at e 2/h in a clean one-dimensional (1D) quantum wire defined by back-gated, split gate devices on a GaAs/AlGaAs heterostructure in the absence of a magnetic field. The 1D devices were fabricated using standard lithography techniques consisting of split gates, and a custom-designed back gate allows for the modulation of carrier density within the 1D channel. The differential conductance shows regular quantised plateaus in units of 2e 2/h as a function of back gate voltage, including the observation of the 0.7(2e 2/h) conductance anomaly. The 0.7 anomaly, on reducing the charge carrier concentration, gradually converts into a 0.5(2e 2/h) structure, indicating the lifting of spin degeneracy in the absence of a magnetic field. Our results suggest the potential of low-density 1D devices for applications in spintronics and quantum electronics.

Abstract InGaN-based green light-emitting diodes with different pre-well numbers were grown by an organometallic vapor phase epitaxy deposition method on patterned sapphire substrates. Micro-LED chips with a size of 17 × 20 μm2 were fabricated, and a peak external quantum efficiency (EQE) of 39% was achieved at ultra-low current density of 0.07 A cm−2. The EQE variation curves of different samples were studied under different current densities. It was confirmed that by reducing the number of pre-wells the Shockley–Read–Hall non-radiative recombination under ultra-low current density was suppressed, which ultimately results in a high EQE of micro-LEDs.

Abstract A vertical GaN p–n junction diode (PND) and junction barrier Schottky diode (JBSD) were fabricated by selective Mg diffusion. Mg was diffused from a shallow N/Mg ion-implantation segment to a depth of 800 nm with a concentration of 1 × 1017–3 × 1018 cm−3 by annealing with an AlN capping layer at 1300 ℃ for 5 min under atmospheric N2 pressure. The PND and JBSD exhibited specific on-resistances of 2.3–2.6 mΩ cm2 and repeatable breakdowns at 1.95 kV without degradation in breakdown voltage or leakage current. Additionally, the JBSD achieved a high-on/off ratio of 9.1 × 107 between 1.5 V and −1 kV.

Abstract Two-dimensional crystallization of chiral molecules on achiral crystal surfaces typically exhibits mirror-imaged growth, defined by the substrate's mirror plane and the lattices of each enantiomer. While various commensurate molecular overlayers have shown such growth, the possibility of achieving substrate-defined enantiospecific structures in non-commensurate chiral molecular overlayers remains elusive. Here, enantiopure thiadiazole-[9]helicene on Au(111) is shown to form overlayers without commensurability, exhibiting substrate-defined mirror-imaged growth. This study experimentally demonstrates that the rotational orientation locking without two-dimensional interface potential minima can support mirror-imaged growth, suggesting that it can serve as benchmark for enantiospecific growth in a broader range of chiral molecular systems.

Abstract X-ray Talbot and Talbot–Lau interferometers consisting of transmission gratings are widely used for X-ray phase imaging, which depicts soft materials. This study exploits the use of a pair of concave and convex parabolic gratings instead of a conventional rectangular phase grating to enhance the phase signal optically. To gain insight into the optimal design, signal enhancement is evaluated by directly measuring the self-image formed downstream of the pair. An increase in the differential phase signals is demonstrated as a function of the distance between the pair, and prospects for deploying this concept into a practical phase imaging technique are discussed.

Abstract Here, we report the first demonstration of a full InGaN-based red LED grown on a c-plane ScAlMgO4 substrate. This work represents a potential approach for achieving red emissions from an InGaN quantum well grown on InGaN underlying layers. The LED device exhibits a peak wavelength of 617 nm at a current injection of 40 mA (10.5 A cm−2). The light output power and external quantum efficiency were 12.6 μW and 0.016% at 40 mA (10.5 A cm−2), respectively. These results are expected to contribute to the development of longer-wavelength emission LEDs and laser diodes.

Abstract This study explores how gallium nitride (GaN) surface polarity affects the optical properties and surface potential of MoS2. Using Raman spectroscopy, photoluminescence, and Kelvin force microscopy (KFM), significant electron doping (~1014 cm-2) was observed in MoS2 on N-face GaN compared to Ga-face. PL spectra and the small contact potential difference of ~30 mV measured by KFM provided evidence for polarity-dependent different doping levels. Additionally, KFM measurements also suggested a small band bending difference between Ga- and N-face GaN, likely due to interactions at the GaN/MoS2 interface. This heavy doping contributes to the improved valley polarization of N-face GaN.