Light harvesting with Ge quantum dots embedded in SiO{sub 2} or Si{sub 3}N{sub 4}

Journal Article · Tue Jan 28 00:00:00 EST 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4863124· OSTI ID:22275636

Cosentino, Salvatore; Raciti, Rosario; Simone, Francesca; Crupi, Isodiana; Terrasi, Antonio; Mirabella, Salvo ^[1]; Sungur Ozen, Emel; Aydinli, Atilla ^[2]; Mio, Antonio M.; Nicotra, Giuseppe ^[3]; Turan, Rasit ^[4]

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1. MATIS IMM-CNR and Dipartimento di Fisica e Astronomia, Università di Catania, via S. Sofia 64, 95123 Catania (Italy)
2. Department of Physics, Bilkent University, 06800 Ankara (Turkey)
3. IMM-CNR, VII strada 5, 95121 Catania (Italy)
4. Department of Physics, Middle East Technical University, 06531 Ankara (Turkey)

Germanium quantum dots (QDs) embedded in SiO{sub 2} or in Si{sub 3}N{sub 4} have been studied for light harvesting purposes. SiGeO or SiGeN thin films, produced by plasma enhanced chemical vapor deposition, have been annealed up to 850 °C to induce Ge QD precipitation in Si based matrices. By varying the Ge content, the QD diameter can be tuned in the 3–9 nm range in the SiO{sub 2} matrix, or in the 1–2 nm range in the Si{sub 3}N{sub 4} matrix, as measured by transmission electron microscopy. Thus, Si{sub 3}N{sub 4} matrix hosts Ge QDs at higher density and more closely spaced than SiO{sub 2} matrix. Raman spectroscopy revealed a higher threshold for amorphous-to-crystalline transition for Ge QDs embedded in Si{sub 3}N{sub 4} matrix in comparison with those in the SiO{sub 2} host. Light absorption by Ge QDs is shown to be more effective in Si{sub 3}N{sub 4} matrix, due to the optical bandgap (0.9–1.6 eV) being lower than in SiO{sub 2} matrix (1.2–2.2 eV). Significant photoresponse with a large measured internal quantum efficiency has been observed for Ge QDs in Si{sub 3}N{sub 4} matrix when they are used as a sensitive layer in a photodetector device. These data will be presented and discussed, opening new routes for application of Ge QDs in light harvesting devices.

• OSTI ID: 22275636
• Journal Information: Journal of Applied Physics, Vol. 115, Issue 4; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
77 NANOSCIENCE AND NANOTECHNOLOGY
ABSORPTION
ANNEALING
CHEMICAL VAPOR DEPOSITION
COMPARATIVE EVALUATIONS
GERMANIUM
QUANTUM DOTS
QUANTUM EFFICIENCY
RAMAN SPECTROSCOPY
SILICON NITRIDES
SILICON OXIDES
THIN FILMS
TRANSMISSION ELECTRON MICROSCOPY
VISIBLE RADIATION