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Optical properties of Zn2SiO4 nanoparticles embedded in SiOx amorphous matrix
|Young-Hwan Kim 1, Woon-Jo Cho 1, Byung Yong You 2, Yong Tae Kim 1|
1. Nano Device Research Center, Korea Institute of Science and Technology (KIST), P.O.Box 131, Cheongryang, Seoul 130-650, Korea, South
Optoelectronic materials compatible with silicon substrates are important from the viewpoint of practical applications for silicon photonics. In this work, we have fabricated Zn2SiO4 nanoparticles embedded in SiOx amorphous matrix showing a strong cathodoluminescent emission in the UV-blue region by adjusting the composition of Zn-Si-O film and post-annealing temperature. The Zn-Si-O films with various compositions of Zn/Si ratio=0.4~11.2 were sputter-deposited on Si (100) substrates by changing area ratio of ZnO to Si target and were post-annealed at the temperatures of 400~1000 °C for 3 minutes in a nitrogen atmosphere by rapid thermal annealing process. Among them, the film with Zn/Si ratio=~1.6, which was annealed at 700 oC, showed a strong and broad cathodoluminescence (CL) emission ranging from 350 to 550 nm. Especially, the UV-blue peak around ~400 nm was remarkable. Weaker UV-blue emission peak was also observed from the film with smaller Zn/Si ratio. However, this UV-blue emission peak disappeared as the Zn/Si ratio increased. The high-resolution TEM analysis showed that the films with Zn/Si ratio below ~1.6 contained Zn2SiO4 nanoparticles with a size of ~5 nm which were distributed in the SiOx amorphous matrix. However, the Zn/Si ratio larger than the optimized value for the formation of Zn2SiO4 nanoparticle caused a formation of nanoparticle-network structure and further increase of Zn/Si ratio resulted in a formation of ZnO film structure. Therefore, the UV-blue emission peak around ~400 nm is thought to be attributed to Zn2SiO4 nanoparticles, which is supported by the fact that the intensity of this UV-blue emission peak increased with increasing the number of Zn2SiO4 nanoparticle. The origin of the strong and broad CL emission containing the UV-blue emission from the Zn-Si-O film with Zn/Si ratio=~1.6, leading to a possible application to Si-based optoelectronic devices, will be discussed analytically.
Presentation: Poster at E-MRS Fall Meeting 2007, Symposium A, by Young-Hwan Kim
See On-line Journal of E-MRS Fall Meeting 2007
Submitted: 2007-05-14 17:23 Revised: 2009-06-07 00:44