Abstract
Ge nanocrystals (NCs) are shown to form within HfO2 at relatively low annealing temperatures (600-700 °C) and to exhibit characteristic photoluminescence (PL) emission consistent with quantum confinement effects. After annealing at 600 °C, sample implanted with 8.4× 1015 Gecm-2 show two major PL peaks, at 0.94 and 0.88 eV, which are attributed to no-phonon and transverse-optical phonon replica of Ge NCs, respectively. The intensity reaches a maximum for annealing temperatures around 700 °C and decreases at higher temperatures as the NC size continues to increase. The no-phonon emission also undergoes a significant redshift for temperatures above 800 °C. For fluences in the range from 8.4× 1015 to 2.5× 1016 cm-2, the average NC size increases from ∼13.5±2.6 to ∼20.0±3.7 nm. These NC sizes are much larger than within amorphous SiO2. Implanted Ge is shown to form Ge NCs within the matrix of monoclinic (m) -HfO2 during thermal annealing with the orientation relationship of [101] m -HfO2 // [110] Ge NC.
Original language | English |
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Article number | 106112 |
Journal | Journal of Applied Physics |
Volume | 105 |
Issue number | 10 |
DOIs | |
Publication status | Published - 2009 |