Silicon oxide and silicon oxynitride thin films with in-situ cerium (Ce) doping were deposited using electron-cyclotron-resonance plasma enhanced chemical-vapor deposition (ECR-PECVD) on p-type silicon substrates. Oxygen was gradually substituted by nitrogen to produce SiOxNy thin films with different layer compositions. Refractive indices extracted from variable-angle spectroscopic ellipsometry (VASE) measurements classified the thin films into two main groups, SiOx and SiOxNy. The thin film composition was studied by Rutherford Backscattering Spectrometry (RBS), verifying the gradual increase in nitrogen content.
Photoluminescence (PL) spectra of samples were obtained using a 375 nm laser diode as an excitation source. All samples were subjected to post-deposition annealing treatment for 1 hour at different temperatures varying from 800 to 1200 °C in both 95% N2 and 5% H2 and pure N2 gas environment, to investigate the effect of hydrogen passivation on the PL irradiance. Samples subjected to annealing yielded considerably stronger blue/white PL emission than as-deposited ones, due to the formation of Ce-containing clusters at a temperature of 1200 °C. Optimum layer composition and annealing condition to produce SiOxNy thin films with maximized Ce3+ excitation efficiency were determined. Besides, the effect of hydrogen fluoride (HF) etching on PL irradiance was studied, showing that an HF (1%) etching duration of 90 s yields the highest PL irradiance.
Electrical measurements were carried out for all Ce doped samples as preliminary work for light-emitting device fabrication. ITO and Al are coated as electrodes on the front side of the thin films and backside of the substrates, respectively, using a radio frequency (RF) magnetron sputtering system. I-V measurements were performed to investigate the carrier injection properties and the dominating mechanism of carrier conduction was determined. / Thesis / Master of Applied Science (MASc)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/25488 |
| Date | January 2020 |
| Creators | Gao, Yuxuan |
| Contributors | Mascher, Peter, Engineering Physics |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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