Styrene acrylic emulsions (SAEs) have emerged as a promising material for water-based coatings. However, they are still limited by their own defects in practical applications, poor weatherability, and degradation of performance at lower or higher temperatures. Here, we introduce a facile approach to producing fluorescent carbon quantum dots (CQDs) from wood processing residues and fabricating fluorescent CQD/SAE coating films via emulsion-casting. The addition of the fluorescent CQDs enhanced the optical performance of the CQD/SAE coating films. The fluorescent CQDs were prepared via a hydrothermal approach and were obtained after heating at 180 °C for 6 h at a reaction concentration of 50 mg/mL. The synthesized CQDs resulted in a high fluorescence, and the CQDs had an average size of 1.63 nm. Various concentrations of the fluorescent CQDs were doped into the SAE coating film, which improved its optical properties. We also characterized and discussed the products and then explored their optical properties. This study presents the potential of fluorescent CQD/SAE coating films for applications in anti-counterfeiting coatings, fluorescent adhesives, and papermaking.

This study optimizes the CuO_x/Ga₂O₃ heterojunction diodes (HJDs) by tailoring the structural parameters of CuO_x layers. The hole concentration in the sputtered CuO_x was precisely controlled by adjusting the Ar/O₂ gas ratio. Experimental investigations and TCAD simulations were employed to systematically evaluate the impact of the CuO_x layer dimension and hole concentration on the electrical performance of HJDs. The results indicate that increasing the diameter dimension of the CuO_x layer or tuning the hole concentration to optimal values significantly enhances the breakdown voltage (V_B) of single-layer HJDs by mitigating the electric field crowing effects. Additionally, a double-layer CuO_x structure (p⁺ CuO_x/p⁻ CuO_x) was designed and optimized to achieve an ideal balance between the V_B and specific on-resistance (R_on,sp). This double-layer HJD demonstrated a high V_B of 2780 V and a low R_on,sp of 6.46 mΩ·cm², further yielding a power figure of merit of 1.2 GW/cm². These findings present a promising strategy for advancing the performance of Ga₂O₃ devices in power electronics applications.

This study presents a β-Ga2O3 Schottky barrier diode (SBD) with a Mg current blocking layer (Mg-CBL) fabricated via the Mg-doped spin-on-glass (Mg-SOG) technique, affording a surface roughness damage-free thermal doping process. The proposed technique improves the breakdown voltage (BV) of the β-Ga2O3 SBD from 580 to 2200 V and marginally increases the specific on-resistance from 4.0 to 4.8 mΩ cm2, yielding a notable power figure of merit exceeding 1 GW/cm2. The Mg-CBL effectively captures the electrons and mitigates the electric field, leading to a significant increase in BV and slight decrease in the forward current loss. The temperature-dependent I–V curves reveal that the reverse saturation current decreases owing to the physical mechanism of the Mg-CBL structure. Moreover, the Gaussian distribution model is applied to correct the Schottky barrier inhomogeneity stemming from the Mg-CBL. The results illustrate the promising potential of the Mg-CBL fabricated via the Mg-SOG technique for yielding high-performance β-Ga2O3 SBDs.

In this study, high-performance InAlN/GaN metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs) are fabricated using HfAlOx-based charge-trapping layer dielectric stack combined with in situ O3 treatment. A positive threshold voltage shift (ΔVTH) of 8.9 V is achieved due to the charge-trapping effect. The device also shows a high Ion/Ioff ratio of ∼1010, a low gate leakage current of ∼10−7 mA/mm, and a relatively high BVDS of 400 V. The suppression of gate leakage current results in an ultra-high gate breakdown voltage of 22.5 V, owing to the superior current blocking capability of the O3-based Al2O3/HfO2 blocking layers and the interface improvement between dielectric and InAlN barrier achieved through in situ O3 treatment. The time-dependent dielectric breakdown measurements reveal the quality and reliability of the dielectric layer, predicting a maximum VGS of 9.66 and 9.31 V for a 10-year lifetime at failure rates of 63.2% and 0.10%, respectively. Additionally, x-ray photoelectron spectroscopy, atomic force microscopy, and multi-frequency C–V measurements further verify the effectiveness of the in situ O3 treatment in the optimization of the dielectric/GaN interface. These results demonstrate a practical approach to significantly improve the performance of InAlN/GaN MIS-HEMTs.

In this work, the DC performance and RF characteristics of GaN-based high-electron-mobility transistors (HEMTs) using the SiN_x stress-engineered technique were systematically investigated. It was observed that a significant reduction in the peak electric field and an increase in the effective barrier thickness in the devices with compressive SiN_x passivation contributed to the suppression of Fowler–Nordheim (FN) tunneling. As a result, the gate leakage decreased by more than an order of magnitude, and the breakdown voltage (BV) increased from 44 V to 84 V. Moreover, benefiting from enhanced gate control capability, the devices with compressive stress SiN_x passivation showed improved peak transconductance from 315 mS/mm to 366 mS/mm, along with a higher cutoff frequency (f_t) and maximum oscillation frequency (f_max) of 21.15 GHz and 35.66 GHz, respectively. Due to its enhanced frequency performance and improved pinch-off characteristics, the power performance of the devices with compressive stress SiN_x passivation was markedly superior to that of the devices with stress-free SiN_x passivation. These results confirm the substantial potential of the SiN_x stress-engineered technique for high-frequency and high-output power applications, which are crucial for future communication systems.