Activating Excellent Electromagnetic Wave Absorption of Micromorphology-Optimized Cu/C Nanocomposite Fibers via a Metal-Organic Framework Template-Assisted Strategy.

Morphological engineering is crucial for conceiving high-efficiency electromagnetic wave (EMW) absorption materials. However, for carbon fiber-based composites, the management of micromorphology is significantly astricted by complex fabrication. It remains highly challenging to clarify the micromorphological influences on the EMW loss mechanism of carbon fiber-based absorption materials. In this work, micromorphology-optimized Cu/C nanocomposite fibers are prepared by virtue of a metal-organic framework (MOF) template-assisted strategy. Through skillfully grafting the morphology-regulation capacity of MOFs onto composite fibers, the Oswald maturation and particle distribution issues of Cu nanoparticles are settled, and the efficient electron transport pathways are established by the bead-like structure of the fiber matrix. Compared to prepared conventional Cu/C nanocomposite fibers, the MOF template-assisted strategy stimulates a remarkable leap in EMW absorption performance. The minimum reflection loss value of Cu/C-40 can reach -64.5 dB, 15.96 times lower than that of a conventional sample (Cu/C-2). The maximum effective absorption bandwidth extends to 6.08 GHz, contrasting the ineffective performance of Cu/C-2. Systematic research demonstrates that the enabled graphite-catalytic function of Cu nanoparticles collaborated with an optimized conductive network structure plays a pivotal role in creating field-induced leakage currents, facilitating conductive loss, the primary contributor to EMW dissipation. This work establishes a correlation mechanism between micromorphology and EMW loss, presenting a compelling example of customizable carbon fiber-based absorbers.

Microstructure Evolution and Electrical Behaviors for High-Performance Cu2O/Zr-Doped ß-Ga2O3 Heterojunction Diodes.

Beta-gallium oxide (ß-Ga2O3) is emerging as a promising ultrawide band gap (UWBG) semiconductor, which is vital for high-power, high-frequency electronics and deep-UV optoelectronics. It is especially significant for flexible wearable electronics, enabling the fabrication of high-performance Ga2O3-based devices at low temperatures. However, the limited crystallinity and pronounced structural defects arising from the low-temperature deposition of Ga2O3 films significantly restrict the heterojunction interface quality and the relevant electrical performance of Ga2O3-based devices. In this work, cuprous oxide (Cu2O)/Zr-doped ß-Ga2O3 heterojunction diodes are fabricated by magnetron sputtering without intentional substrate heating, followed by an investigation into their microstructure and electrical behaviors. Zr doping can markedly enhance the Ga2O3 crystallinity at low substrate temperatures, transforming the amorphous structure of pristine Ga2O3 films into the crystallized ß phase. Moreover, crystalline ß-Ga2O3 facilitates the epitaxial growth of the Cu2O phase, suppressing the formation of detrimental secondary phase CuO at the heterojunction interface. Benefiting from the high-quality heterojunction interface, the Cu2O/Zr-doped ß-Ga2O3 heterojunction diode exhibits a near-ideal electrical behavior with a low ideality factor of 1.6. The consistent electrical parameters extracted from current-voltage (J-V) and capacitance-voltage (C-V) measurements also confirm the high quality of ß-Ga2O3. This work highlights the potential for the low-temperature production of high-quality ß-Ga2O3-based heterojunction devices through Zr doping.