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Germanium quantum dots (QDs) embedded in SiO2or in Si3N4have 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 SiO2matrix, or in the 1-2 nm range in the Si3N4matrix, as measured by transmission electron microscopy. Thus, Si3N4matrix hosts Ge QDs at higher density and more closely spaced than SiO2matrix. Raman spectroscopy revealed a higher threshold for amorphous-to-crystalline transition for Ge QDs embedded in Si3N4matrix in comparison with those in the SiO2host. Light absorption by Ge QDs is shown to be more effective in Si3N4matrix, due to the optical bandgap (0.9-1.6 eV) being lower than in SiO2matrix (1.2-2.2 eV). Significant photoresponse …
American Institute of Physics Publising LLC
Publication date: 
1 Jan 2014

Isodiana Crupi, Giuseppe Nicotra, Atilla Aydinli, Francesca Simone, Rasit Turan, Salvo Mirabella, Antonio M Mio, Salvatore Cosentino, Emel Sungur Ozen, Antonio Terrasi, Rosario Raciti

Biblio References: 
Volume: 115
Journal of Applied Physics