Intense ultraviolet photoluminescence at room temperature in As-deposited Si : H : O films

Three photoluminescence (PL) bands at 340-370, 400-430, and 740 nm were obs erved at room temperature in a-Si:H:O films fabricated by plasma enhanced c hemical vapor deposition without any post-processing. The violet-blue emiss ion is very strong and stable, and its intensity is closely related to the oxygen content in the films, which can be controlled by the applied de bias es on the sample substrates during deposition. The first two PL peaks are a scribed to oxygen-related colour centers in the a-Si:H:O matrix, and the la st one is ascribed to the quantum size effect of the nanocrystallites embed ded in a-Si:H:O matrix and the colour centers in the crystallites interface s.