Laser surface structuring has been demonstrated to be a versatile technology to create various functional materials by modifying solid surface properties. An interesting experimental phenomenon of self-organized periodic microholes array formation is demonstrated by exposing an aluminum surface to femtosecond laser irradiation. The microholes with a diameter much smaller than focal laser spot size are produced along laser scan paths due to the incubation effect of multiple laser scans, and they spontaneously form a highly ordered microholes array after 80 scans. It is found that the microhole period and diameter are highly dependent on laser fluence, and controllable microholes arrays with different periods and diameters are achieved by adjusting laser fluence. The physical mechanism behind the formation of the microholes array is attributed to femtosecond laser-induced melting and Marangoni effect. The research provides a novel processing approach to achieve controllable microholes surface materials fabrication at a high speed on metal substrates, which are of great interests for various technological applications.

A one‐step laser lift‐off (LLO) for patterned gallium nitride (GaN) film and GaN‐based light‐emitting diode (LED) device is achieved using 355 nm picosecond laser irradiation in this research. The laser fluence required for separation is 0.09–0.13 J cm−2, which is much lower than that for the currently reported LLO methods. The separated GaN film is intact with only 0.04 GPa of residual stress. The ultra‐smooth separated surface with root mean square roughness of only 5.2 nm is attributed to the interconnection of microcrack‐free flat cavities formed by the combination of high photon energy‐induced intrinsic absorption and subsequent plasma generation. The flat cavity with a depth‐to‐width ratio of 1:4000 limits the delamination region to a few nanometers at the GaN/sapphire interface. GaN‐based LED is transferred with perfect electroluminescence (EL) by the strategy. The stable EL spectral peak positions and intensity independent of the bending state prove that the presented low‐energy ultrafast LLO technique ensured the flexibility of the separated LED device without affecting the performance. This research provides a promising strategy to achieve the LLO of GaN devices with low energy consumption, high controllability, and high efficiency, which is significant for the industrial fabrication of flexible GaN‐based electronics.

Blue photoluminescence (PL) of 6H-SiC irradiated by an ultraviolet laser can be observed at room temperature in dark condition. PL spectra with Gaussian fitting curve of the irradiated SiC show that blue luminescence band (∼440 nm) is more pronounced than other bands. The blue PL enhancement is the combined result of the improved shallow N-donor energy level and the unique surface state with Si nanocrystals and graphene/Si composite due to the effect of photon energy input by the short-wavelength laser irradiation. The study can provide a promising route towards the preparation of well-controlled blue photoluminescence material for light-emitting devices.

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