Nanocrystallized Ge-Rich SiGe-HfO<sub>2</sub> Highly Photosensitive in Short-Wave Infrared
Group IV nanocrystals (NCs), in particular from the Si–Ge system, are of high interest for Si photonics applications. Ge-rich SiGe NCs embedded in nanocrystallized HfO<sub>2</sub> were obtained by magnetron sputtering deposition followed by rapid thermal annealing at 600 °C for nanostruc...
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| Autores principales: | , , , , , , , |
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| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
MDPI AG
2021
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| Materias: | |
| Acceso en línea: | https://doaj.org/article/c6011a9370384f2894af748a47ad2511 |
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| Sumario: | Group IV nanocrystals (NCs), in particular from the Si–Ge system, are of high interest for Si photonics applications. Ge-rich SiGe NCs embedded in nanocrystallized HfO<sub>2</sub> were obtained by magnetron sputtering deposition followed by rapid thermal annealing at 600 °C for nanostructuring. The complex characterization of morphology and crystalline structure by X-ray diffraction, μ-Raman spectroscopy, and cross-section transmission electron microscopy evidenced the formation of Ge-rich SiGe NCs (3–7 nm diameter) in a matrix of nanocrystallized HfO<sub>2</sub>. For avoiding the fast diffusion of Ge, the layer containing SiGe NCs was cladded by very thin top and bottom pure HfO<sub>2</sub> layers. Nanocrystallized HfO<sub>2</sub> with tetragonal/orthorhombic structure was revealed beside the monoclinic phase in both buffer HfO<sub>2</sub> and SiGe NCs–HfO<sub>2</sub> layers. In the top part, the film is mainly crystallized in the monoclinic phase. High efficiency of the photocurrent was obtained in a broad spectral range of curves of 600–2000 nm at low temperatures. The high-quality SiGe NC/HfO<sub>2</sub> matrix interface together with the strain induced in SiGe NCs by nanocrystallization of both HfO<sub>2</sub> matrix and SiGe nanoparticles explain the unexpectedly extended photoelectric sensitivity in short-wave infrared up to about 2000 nm that is more than the sensitivity limit for Ge, in spite of the increase of bandgap by well-known quantum confinement effect in SiGe NCs. |
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