Study of photoluminescence spectrum in p-type α-porous silicon carbide

The photoluminescence (PL) spectra from p-type α-porous silicon carbides prepared under UV photo-assisted process and under dark-current condition are investigated in detail. Emission bands with peak energies of 2.35, 2.50, 2.70 and 3.43 are resolved. The PL stability in time and the PL difference arising from different tuning excitation energies are studied. It is found that the PL spectra of the α-porous silicon carbide depend strongly on the preparation conditions for electrochemical etching. The PL spectrum of the sample prepared under photo-assisted process has an enhancement on the lower-energy side of the emission; on the contrary, another one under dark-current condition has an enhancement at the higher energy side, and the former stability is better than the latter one, and the latter PL intensity decreases with the increase of the time in the air. The reasons about these differences are discussed