Plasma power controlled PECVD of SiO(x) under SiH(4)/N(2)O gas mixture with manipulated Si quantum dot (Si-QD) size for tailoring photoluminescent (PL) wavelength is demonstrated. The incomplete decomposition of N(2)O at high plasma power facilitates Si-rich SiO(x) deposition to enlarge O/Si composition ratio and to shrink Si-QD size. As RF plasma power increases from 20 to 70 W, the O/Si ratio is increased from 1 to 1.6 and the average Si-QD size is reduced from 4.5 to 1.7, which increases Si-QD density from 3.2 x 10(17) to 3.02 x 10(18) cm(-3) and blue-shifts PL wavelength from 780 to 380 nm.