Tuning the Photoluminescence Peak Position of Si Nanocrystals by Chemical Etching

Silicon nanocrystals doped with silicon dioxide (Si-NCs:SiO₂) are a promising silicon (Si)-based light-emitting material. However, their low efficiency and difficulty tuning their light emission have hindered the practical use of Si-NCs:SiO₂. We used facile approaches to prepare highly luminescent Si-NCs:SiO₂ from hydrogen silsesquioxane (HSQ), and to tune the light emission by chemical etching. Characterizations were conducted using transmission electron microscopy, photoluminescence (PL) and Raman spectroscopy to acquire information on their structure, nanocrystal size, light emission properties, and other characteristics. As compared to Si-NCs:SiO₂ prepared by the regular method of phase separation of silicon oxide (SiOx) (1 < x < 2), the Si-NCs:SiO₂ prepared from HSQ is more luminescent and the PL peak position is readily tunable by chemical etching. PL peak positions of 570 nm, 610 nm and 730 nm of Si-NCs:SiO₂ have been obtained.