Abstract
The effects on the photoluminescence (PL) from Si nanocrystals embedded in a SiO 2 matrix (Si-NCs/SiO 2 ) by annealing in air have been examined, and the correlation between the PL properties and the passivation of luminescence-quenching defects at the Si nanocrystal/SiO 2 interface has been studied. Si-NCs/SiO 2 were fabricated by annealing amorphous silicon suboxide (a-SiO x ) in a N 2 atmosphere at 1100°C and the passivation of Si-NCs/SiO 2 was performed by annealing Si-NCs/SiO 2 in air at temperatures ranging from 400 to 800°C for varied times. The heating of Si-NCs/SiO 2 in air is very effective for passivating dangling bonds and an enhancement about 5 times in PL intensity was obtained. High-temperature passivation in air is accompanied by oxidation of Si nanocrystals. Additional N 2 -treatment of the passivated Si-NCs/SiO 2 at elevated temperatures depassivates Si-NCs/SiO 2 , generating new dangling bonds which can also be passivated in the subsequent repassivation process. The effect of passivation on the PL intensity is reversible, while high-temperature passivation results in an irreversible blue shift of PL spectra. PL decay time can be indicative of passivating or generating of dangling bonds.
| Original language | English |
|---|---|
| Pages (from-to) | 804-809 |
| Number of pages | 6 |
| Journal | Applied Surface Science |
| Volume | 320 |
| DOIs | |
| State | Published - 30 Nov 2014 |
Keywords
- Passivation
- Photoluminescence
- Photoluminescence decay time
- Photoluminescence enhancement
- Si nanocrystal