Morphology and photoluminescence of anodized aluminium-coated 6H-SiC samples

In this work, we report the effect of surface modification by aluminum metallization, prior to anodization in a solution of HF/Ethylene glycol, on the morphology and photoluminescence of p-type porous SiC. For this purpose, a thin metallic film of aluminum has been deposited on a highly resistive 6H-SiC. The morphology of the porous SiC layer has been investigated by Scanning Electron Microscopy (SEM). The results show that aluminum play a crucial role on the dissolution of SiC; it initiates and facilitates the electrochemical etching. The photoluminescence spectra of the anodized Al-coated samples exhibit two emission bands centered at about 430 nm and 560 nm. While for the uncoated samples, a strong luminescence with a peak located at 560 nm is observed. Finally, the role of Al on the photoluminescence mechanism is discussed. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)