Experimental investigations into the formation of nanocrystal silicon thin film synthesized at low substrate temperature

• As opposed to nucleation in the film, nc-Sis crystallization formed in the plasma.
• Surface composition of nc-Sis synthesized at different powers has been studied.
• The nc-Si films show obvious phase separation without high-temperature annealing.

In this study, nanocrystal silicon (nc-Si) films were synthesized via radio-frequency plasma-enhanced chemical-vapor deposition with argon and hydrogen diluted silane. In such a high-density reactive plasma medium, nc-Sis are formed in the plasma first and are then deposited into the film by the fast gas flow. The plasma electronic diagnostics indicate nanoparticle formation in the plasma, as opposed to solid-state nucleation of the nanoparticles in the film. The construction and photoluminescence (PL) were investigated. As power provided to the plasma source increases, the particles transition from amorphous to crystalline, and a corresponding increase in the fraction of hydrogen bonded on a crystalline silicon surface is observed. The oxidized nc-Si films show obvious phase separation without high-temperature annealing. Further, PL measurements show that the increase in photoluminescence intensity of nc-Si films after oxidation is due to an efficient surface passivation with oxygen.