Radiation polarization of silicon carbide p-n-structures, operating in electrical breakdown regime

The spectral dependence of the linear polarization degree of the electroluminescence that accompanies the electrical breakdown of the alloyed p-n-structures prepared on the basis of 4H-, 6H-, 15R-, and 3C-SiC polytypes in the region of 1.4–3.8 eV has been obtained. The structures were located on the crystal faces parallel and perpendicular to the crystallographic C-axis. The radiation was extracted from a thin p-region at an acute angle and also perpendicular to a working face of a crystal. The radiation components which were linearly polarized in the planes parallel and perpendicular to the crystallographic C-axis (E‖C, E⊥C) and parallel to the vector F of the electric field intensity (E‖F) in a p-n-junction have been revealed. It turned out that the spectrum position and the intensity of the components associated with the C-axis direction differ essentially depending on the polytypes. It has been revealed that the presence of the radiation polarization with the degree of 0.3–0.4 in the plane E‖C in the fundamental absorption region and in the adjacent region is common for all polytypes. Only in 6H- and 15R-SiC polytypes did the optical absorption data correspond to the radiation polarization characteristics. The polarization E‖F achieved the degree of 0.5 and had a tendency to increase towards the higher photon energies.