Light emission from cBN crystal synthesized at high pressure and high temperature

The light emission at a wavelength of about 400nm is observed from the nonintentionally doped n-cubic boron nitride crystal, when the avalanche breakdown occurs inside the cBN crystal that is prepared by hexagonal boron nitride at high pressure and high temperature using nitride as catalyst. The measured spectrum has a peak in the blue-violet range. It shows the electronic transition between valleys of the conduction band of the cBN crystal. At the same time, the current-controlled differential negative resistance phenomenon occurs as well.