Novel porous flower-like NiO@graphene composites with superior microwave absorption properties dues to good impedance matching, the special porous flower-like structure, polarization effects and conductivity loss.

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The high-quality semipolar (112̅ 2) AlGaN epitaxial films have been obtained on m-plane sapphire by metal−organic chemical vapor deposition. X-ray rocking curve measurements show the full-width at halfmaximums of semipolar (112̅ 2)-oriented AlGaN films are 0.357°and 0.531°a long [112̅ 3̅ ] AlGaN and [11̅ 00] AlGaN , respectively. The fabricated semipolar AlGaN metal−semiconductor−metal solar-blind ultraviolet (UV) photodetector (PD) exhibits a high responsivity of 1842 A/W. The fast response and reliability of the UV PD are ensured via fast switching with a rise and decay time of 90 ms and 53(720) ms, respectively. The UV PD exhibits a significant reduction in the dark current, that is, from 100 μA to 780 fA at 10 V, using a simple wet chemical etching to modify the surface properties of materials. The photo-to-dark-current ratio value of the etched UV PD reaches 4 orders of magnitude higher than the unetched UV PD under 270 nm illumination. These are attributed to the fact that KOH wet etching assists in eliminating the surface states and reconstructing the surface oxides. This work might provide a new potential for the development of solar-blind UV PDs with high performance.