Bright luminescence in amorphous hydrogenated silicon-nitride quantum-dot films prepared by a special designed PECVD system

Amorphous hydrogenated silicon-nitride (a-SiNx:H) quantum-dot (QD) films were successfully deposited on Si substrates using a specially designed system of plasma enhanced chemical vapor deposition. The a-SiNx:H QD films exhibit strong visible photoluminescence (PL) with a tunable peak energy ranging from 3.26 to 2.52 eV, depending on the deposition pressure. The PL process was studied in terms of temperature-dependent and time-resolved PL spectra in comparison with the theoretical predication of the band-tail luminescence, and then the tunable PL spectra were assigned to the recombination of excitons in the localized states at the band tails of the a-SiNx:H QDs.