Photoluminescence of porous silicon prepared from pressure treated Cz-Si

Photoluminescence (PL) of porous silicon (pSi) prepared from Czochralski silicon (Cz-Si) annealed up to 1620 K at enhanced pressure of argon up to 1 GPa (HP-HT treatment) was investigated. The intensity of PL with maximum at 660-720 nm decreases with the pressure for pSi prepared from the substrates treated at less than or equal to 1400 K, and increases with the pressure For pSi prepared from the substrates treated at 1620 K. The pSi films prepared from the HP-HT treated substrates were relaxed, contrary to those on the substrates annealed at 1620 K for 30 min at 10(5) Pa. Although our results revealed that photoluminescence properties of pSi depend significantly on the presence of defects created during the oxygen precipitation process, the role of other defects such as non-radiative recombination centres and metallic contamination should be still under consideration.