Stress dependence of the cathodoluminescence spectrum of N-doped 3C-SiC

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The stress dependence of the room-temperature cathodoluminescence spectrum of N-doped cubic silicon carbide has been evaluated in a field-emission-gun scanning electron microscope, using the electron beam as an excitation source for luminescence emission. The electron-stimulated spectrum was dominated by only one broad band centered at about 544nm, with a broad shoulder centered at a slightly lower energy level (≈572nm). The cathodoluminescence spectrum, which was attributed to the four-particle N-bound excitonic transition, arose from substitutional N in the cubic silicon carbide lattice. Using experimentally measured probe response functions and energy shift magnitude collected near the tip of a Vickers indentation microcrack, it was possible to retrieve the actual magnitude of the piezospectroscopic coefficient [i.e., the slope of a linear plot of spectral band shift versus the trace of the stress tensor: Π=0.61±0.02nm∕GPa] of the N-bound exciton (cumulative) band of cubic silicon carbide.