[Measurement and analysis of blue-violet light emitting spectrum on tiny cubic boron nitride crystal]

The electroluminescence effect can be observed by the micro N-type wide-gap CBN semiconductor crystal under the condition of static eletric field. The micro N-type CBN crystal was fixed on the focus of the parabolic reflector of grating monochromator, and the maximum value of transmission ratio and the ideal signal-noise ratio can be obtained. Under the condition of static ectric-field intensity (4.7 x 10(6) V x cm(-1)), the blue-violet light-emitting spectrum of the CBN crystal was measured in the range from 350 to 450 nm. The construction of the CBN energy band, which was calculated with the First-principles method, the nonlinear relationship between current density and the ectric-field intensity that was measured and the phenomenon of electrical break-down were considered together to enable us to discuss the luminescence mechanism. Finally, the authors came up with the luminescence mechanism concerning electron migration from gamma energy valley to X energy valley. The large number of excited electrons we talked about were generated by polarization and breakdown of defect dipole before avalanche breakdown occurred.