Pre-irradiation memory effect on the photoluminescence intensity of Ge-implanted SiO 2 layers

• Published in: Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms Vol. 218; pp. 438 - 443
• Main Authors: Lopes, J.M.J., Zawislak, F.C., Fichtner, P.F.P., Behar, M., Rebohle, L., Skorupa, W.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 2004
• Subjects: Ion irradiation; Nanoclusters; Photoluminescence; SiO 2; Ion irradiation; Photoluminescence; Nanoclusters; 78.55.−m; SiO 2; 61.80.Jh; 78.67.Bf
• ISSN: 0168-583X; 1872-9584
• DOI: 10.1016/j.nimb.2003.12.025

180 nm thick SiO 2 layers thermally grown on crystalline Si were irradiated with He +, Si +, Kr ++ and Au + ions transferring different amounts of electronic ( S e) and nuclear ( S n) energy to the film. After the irradiation, the SiO 2 layers were implanted with 120 keV Ge + ions at a fluence of 1.2 × 10 16 cm −2. Thermal annealings in the 400–800 °C temperature range were performed to allow the formation of Ge-nanoclusters, characterized by transmission electron microscopy. The photoluminescence (PL) properties of the pre-irradiated Ge-implanted layers were investigated and compared with those from non-pre-irradiated samples. The results showed that, in both situations, PL emissions are observed in the blue-violet and ultra-violet spectral regions. At 800 °C the blue-violet PL intensity of the Ge-implanted layer pre-irradiated with Si + ions is about 65% higher than in the non-pre-irradiated Ge-implanted layer while for the Au-irradiated layer a decrease by a factor of ≈6 was observed. Furthermore, we also observe that the mean cluster sizes are affected by the pre-irradiation. These data indicate a pre-irradiation memory effect on the PL intensity and on the cluster growth. The results are discussed in terms of a new model correlating the formation of PL luminescence centers with the cluster coarsening behavior.