The world‐wide spreading of coronavirus disease (COVID‐19) has greatly shaken human society, thus effective and fast‐speed methods of non‐daily‐life‐disturbance sterilization have become extremely significant. In this work, by fully benefitting from high‐quality AlN template (with threading dislocation density as low as ≈6×10 8 cm −2 ) as well as outstanding deep ultraviolet (UVC‐less than 280 nm) light‐emitting diodes (LEDs) structure design and epitaxy optimization, high power UVC LEDs and ultra‐high‐power sterilization irradiation source are achieved. Moreover, for the first time, a result in which a fast and complete elimination of SARS‐CoV‐2 (the virus causes COVID‐19) within only 1 s is achieved by the nearly whole industry‐chain‐covered product. These results advance the promising potential in UVC‐LED disinfection particularly in the shadow of COVID‐19.

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Optical properties of AlGaN UVC multiple-quantum-wells (MQWs) with nanoscale inverted polarity domains are strongly related to polar surfaces and nanoscale structures. In this work, the impact of pregrowth nitridation of the sapphire substrate on the polarity control of UVC MQW is highlighted, and the optical properties of III- and N-polar domains were distinguished. Nanoscale cathodoluminescence peak separation of more than 30 nm is observed in lateral-polarity-structure (LPS) UVC MQWs, which is ascribed to the potential minima induced by the local variation of QW thickness and Ga enrichment inside N-polar domains. After an AlGaN/AlN superlattice is inserted and the V/III ratio is enhanced during growth, the surface morphology of the N-polar domain is greatly improved, leading to a single-peak emission at a wavelength of 275 nm in both the III- and N-polar domains, and a 10-fold stronger peak intensity at the inversion domain boundary. Such understandings on the polar surface optimization and underlying reasons of peak separation enable rational design for efficient UVC emitters with improved performance.

High quality and crack-free AlN films were obtained by using nano-patterned sapphire substrates (NPSS) grown at AMEC Prismo HiT3 TM MOCVD platform. It is believed that the introduced epitaxial lateral overgrowth can annihilate most of dislocations and the grain boundary induced tensile stress can be significantly suppressed by NPSS. For a 5 μm thick AlN film, FWHMs of 173 arcsec and 335 arcsec were observed from AlN ( 002) and (102) X-ray rocking curves, respectively, indicating the high crystalline quality. The surface of AlN films grown on NPSS shows a typical stepbunching morphology with atomic steps on the bunched terrace. In addition, we also obtained excellent thickness uniformity for AlN films grown on NPSS with within-wafer and wafer-to-wafer thickness uniformity of 0.69% and 0.92%, respectively.

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