Photoluminescence from nanocrystallites embedded in hydrogenated amorphous silicon films prepared by plasma enhanced chemical vapor deposition

Abstract
We report in this letter the observation of visible photoluminescence (PL) at room temperature from nanocrystallites embedded in hydrogenated amorphous silicon films, which are prepared in a plasma enhanced chemical vapor deposition system by using strong hydrogen-diluted silane as the reactant gas source, without any post-processing. The PL is attributed to the radiative recombination process of carriers in the nanocrystallites, and the quantum size effect is responsible for the emission above the band gap of bulk crystal Si. The critical deposition parameters of this type of film are identified.