Band-edge luminescence of deformed hexagonal boron nitride single crystals

We studied deformation effects on band-edge luminescence of pure hexagonal boron nitride single crystals. After simple deformation of the single crystals at room temperature, the band-edge luminescence showed a dramatic change, originating from stacking disorder, in the peak wavelength. It changed from 215 nm in a free exciton band to 227 nm in a bound exciton band. This 227-nm bound exciton luminescence has a fast radiative decay time (below a few ns).