CUED Publications database

Defect Emission and Optical Gain in SiCxOy:H Films.

Lin, Z and Li, H and Huang, R and Zhang, Y and Song, J and Li, H and Guo, Y and Song, C and Robertson, J (2017) Defect Emission and Optical Gain in SiCxOy:H Films. ACS Appl Mater Interfaces, 9. pp. 22725-22731. ISSN 1944-8244

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Luminescent SiCxOy:H films, which are fabricated at different CH4 flow rates using the plasma-enhanced chemical vapor deposition (PECVD) technique, exhibit strong photoluminescence (PL) with tuning from the near-infrared to orange regions. The PL features an excitation-wavelength-independent recombination dynamics. The silicon dangling bond (DB) defects identified by electron paramagnetic resonance spectra are found to play a key role in the PL behavior. The first-principles calculation shows that the Si DB defects introduce a midgap state in the band gap, which is in good agreement with the PL energy. Moreover, the band gap of a-SiCxOy:H is found to be mainly determined by Si and C atoms. Thus, the strong light emission is believed to result from the recombination of excited electrons and holes in Si DB defects, while the tunable light emission of the films is attributed to the substitution of stronger Si-C bonds for weak Si-Si bonds. It is also found that the light emission intensity shows a superlinear dependence on the pump intensity. Interestingly, the film exhibits a net optical gain under ultraviolet excitation. The gain coefficient is 53.5 cm-1 under a pumping power density of 553 mW cm-2. The present results demonstrate that the SiCxOy system can be a very competitive candidate in the applications of photonics and optoelectronics.

Item Type: Article
Uncontrolled Keywords: defect optical gain photoluminescence plasma-enhanced chemical vapor deposition silicon oxycarbide
Divisions: Div B > Solid State Electronics and Nanoscale Science
Depositing User: Cron Job
Date Deposited: 17 Jul 2017 19:08
Last Modified: 13 Apr 2021 08:51
DOI: 10.1021/acsami.7b06118