Enhanced electroluminescence efficiency of oxidized amorphous silicon nitride light-emitting devices by modulating Si∕N ratio

The authors had reported green-yellow electroluminescence (EL) from N-rich oxidized amorphous silicon nitride (a-SiN:O) light-emitting devices (LEDs) in a previous work. In this work, a significantly enhanced EL intensity was obtained in the LED by employing Si-rich a-SiN:O instead of N-rich a-SiN:O as luminescent active layer. Moreover, the Si-rich a-SiN:O devices also exhibit lower turn-on voltage and the external quantum efficiency is found to be three times higher than that of the N-rich a-SiN:O devices. The electrical characteristics analyses reveal that the injection barrier for Si-rich a-SiN:O devices is reduced by 30% compared to that of N-rich a-SiN:O devices, which results in a remarkably enhanced carrier-injection efficiency and gives rise to the notable improved performances of the LEDs.