The photoluminescence of multicolor silicon

ABSTRACTThe present paper deals with the photoluminescence (PL) of the multicolor silicon (MC-Si) – a nanocrystalline layer produced by the surface structure chemical transfer (SSCT) method on the p-type Si. The PL behaviours recorded at room temperature are compared with ∼500-nm-thick porous Si prepared electrochemically in the HF + methanol solution on the same Si substrate. The PL spectra of porous Si are shifted to higher energy in comparison with MC-Si. The PL records were fitted by Gaussian curves. We attribute the PL band of porous Si with maximum 2.3 eV to the own luminescence of ∼2.5-nm-thick nanocrystalline Si grains observed due to quantum confinement. This PL band is missing in the PL spectra of MC-Si structures due to the absence of Si nanocrystals of similar size. The PL bands of both MC-Si and porous Si between 1.89 and 2.05 eV are connected with SiO(x) compounds covering the surfaces of Si nanocrystals. Additional two PL bands of all MC-Si structures at 1.69–1.70 eV and 1.80–1.84 eV we rel...