Effect of SiO2 layers on electroluminescence from Si nanocrystal/SiO2 superlattices prepared using argon ion beam assisted sputtering

• This study characterized the effect of IBAS on the SiO2 in Si NCs/SiO2 LED.
• The increase in the density of the SiO2 layers by IBAS process.
• The dense SiO2 layer enhanced the EL efficiency through the low charge loss rate.
• Increased ΦB and Vturn-on in IBAS device were due to the improved SiO2 quality.
• TEM revealed the IBAS did not affect the size or distribution of the Si NCs.

This study investigated the electroluminescence (EL) properties of Si-rich oxide (SRO)/SiO2 superlattices light emitting devices (LEDs). Each SiO2 layer of the superlattices was prepared by using argon ion beam assisted sputtering (IBAS). Transmission electron microscopy revealed that the treatment of Ar ion beams on the SiO2 layers did not affect the size or distribution of the Si nanocrystals in the SRO layers, but enhanced the thin-film quality of the SiO2 and formed a clear SiO2/SRO interface. The refractive index of SiO2 was increased by IBAS because of an increase in the density of SiO2. The EL efficiency was doubled for the IBAS device compared with that of a reference device. According to the retention property, the enhanced EL intensity of the IBAS device was ascribed to lower the charge loss rate through enhancing injection barrier of SiO2. The mechanism of the EL enhancement of the IBAS LED was discussed.