The electric properties and the current-controlled differential negative resistance of cBN crystal

The electric properties of nonintentionally doped n-cubic boron nitride(cBN) crystal are investigated.The cBN crystal was transformed from hexagonal-boron nitride(h-BN) under high pressure(HP) and high temperature(HT) using magnesium powder as catalyst.At room temperature,the current-voltage(I-V) characteristics of cBN crystal are measured and found to be nonlinear.When the electric field is in the range of(1―1.5)×105 V/cm,the avalanche breakdown occurs inside the whole cBN crystal.At this same time,the bright blue-violet with the wavelength of 380―400 nm from the cBN crystal is observed.When measuring the I-V curve after breakdown of cBN crystal,the current-controlled differential negative resistance phenomenon is observed.The breakdown is repeatable.