Fabrication of Nanocrystalline Silicon Gratings Embedded within a Silicon Nitride Matrix by Femtosecond Laser-Induced Crystallization
Nanocrystalline silicon gratings were fabricated by applying both femtosecond-laser-interference crystallization and post thermal annealing to amorphous silicon (a-Si) nanoclusters embedded within a silicon nitride matrix. Catalytic chemical vapor deposition was used to fabricate the embedded a-Si n...
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| Published in: | Japanese Journal of Applied Physics Vol. 49; no. 1; pp. 015502 - 015502-4 |
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| Main Authors: | , , , , , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
The Japan Society of Applied Physics
01-01-2010
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| Online Access: | Get full text |
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| Summary: | Nanocrystalline silicon gratings were fabricated by applying both femtosecond-laser-interference crystallization and post thermal annealing to amorphous silicon (a-Si) nanoclusters embedded within a silicon nitride matrix. Catalytic chemical vapor deposition was used to fabricate the embedded a-Si nanoclusters, and the formation of a-Si nanoclusters was confirmed by photoluminescence spectroscopy. The femtosecond laser interference technique was employed to produce a seed pattern for the spatially-selected crystallization of a-Si nanoclusters. Micro-Raman spectroscopy and selected-area electron diffraction, together with high-resolution transmission-electron microscopy, show that nanocrystalline silicon gratings were formed through an amorphous-to-crystalline transformation with femtosecond laser pulses, and that the degree of crystallization was enhanced by applying post thermal annealing to the seed gratings. |
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| Bibliography: | (Color online) Experimental setup for recording the nanocrystalline silicon grating using the femtosecond laser interference technique: L, convex lens; M, mirror; BS, beam splitter; W, half wave plate; P, polarizer; Sh, beam shutter; Ap, aperture; BB, beam block; PD, photo detector; TS, translation stage. Transmission spectra of the as-deposited film. (Color online) PL spectra of the as-deposited film at three different temperatures (8, 150, and 300 K). (Color online) Diffraction behavior of the probe beam from the nanocrystalline silicon grating produced within the silicon nitride matrix using two interfering femtosecond laser pulses. The pulse energies of the two writing beams are 5.7 \mbox{$\mu$}J and 5.7 \mbox{$\mu$}J. In the illustration of grating formation dynamics, the horizontal bar represents the writing period of two interfering beams for recording the nanocrystalline silicon grating. (Color online) Micro-Raman spectra for the nanocrystalline silicon gratings (a) before and (b) after post thermal annealing. Nanocrystalline silicon gratings were produced within a silicon nitride matrix using femtosecond laser interference crystallization. For (a), the nanocrystalline silicon gratings were fabricated using 1000 (F1) and 9000 (F2) shots from two 5.7 \mbox{$\mu$}J beams. For (b), post thermal annealing of the seed gratings was performed at 500 \mbox{ \circ C} for 5 h in a nitrogen atmosphere. (Color online) (a) Plan-view TEM image for the nanocrystalline silicon grating produced within the silicon nitride matrix using both femtosecond laser interference crystallization and post thermal annealing. (b) SAED pattern for the crystallized band of the nanocrystalline silicon grating after post thermal annealing. (c) SAED pattern for the unexposed region in the sample film after post thermal annealing. (d) HRTEM images for the crystallized band of the nanocrystalline silicon grating after post thermal annealing. |
| ISSN: | 0021-4922 1347-4065 |
| DOI: | 10.1143/JJAP.49.015502 |