Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8035669 | Thin Solid Films | 2017 | 6 Pages |
Abstract
Post-annealing and regrowth of Ge were investigated to improve the crystallinity and to control the lattice strain of Ge layers directly grown on a Si substrate by low-temperature epitaxial growth. The post-annealing at a higher temperature was an effective way of improving the surface morphology and the crystallinity of the Ge layers. Furthermore, the lattice strain changed from compressive to tensile in < 110 > crystal orientation when the post-annealing temperature was increased, and the tensile strain of 0.19% was achieved at the annealing temperature of 700 °C. Consequently, the photoluminescence (PL) intensity increased with the increasing post-annealing temperature and a red-shift of the PL spectra could be observed due to reduction of direct bandgap energy at Ð-point with the tensile strain. Although regrowth of the Ge layers had little impact on the lattice strain at a relatively low regrowth temperature, a thick Ge layer with high crystallinity was formed at 700 °C and a favorable PL spectrum was obtained. These results indicate that this combined technique can improve the performance of Ge light-emitting devices.
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Related Topics
Physical Sciences and Engineering
Materials Science
Nanotechnology
Authors
Katsuya Oda, Kazuki Tani, Shin-ichi Saito, Tatemi Ido,