Extraordinary and stable long wavelength emission centered at 685 nm from the yard-glass shaped boron nitride nanotubes YG-BNNTs was observed in their cathodoluminescence and photoluminescence spectroscopy. The mechanism for this near-red light emission at 685 nm is attributed to the periodical nature of the BNNT units with regular lattice defects. The visible-light emission from YG-B…