Research output: Contribution to journal › Article › peer-review
Ge nanocrystals formed by furnace annealing of Ge(x)[SiO2](1-x) films: Structure and optical properties. / Volodin, V. A.; Cherkov, A. G.; Antonenko, A. Kh et al.
In: Materials Research Express, Vol. 4, No. 7, 075010, 01.07.2017.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Ge nanocrystals formed by furnace annealing of Ge(x)[SiO2](1-x) films: Structure and optical properties
AU - Volodin, V. A.
AU - Cherkov, A. G.
AU - Antonenko, A. Kh
AU - Stoffel, M.
AU - Rinnert, H.
AU - Vergnat, M.
PY - 2017/7/1
Y1 - 2017/7/1
N2 - Ge(x)[SiO2](1-x) (0.1 ≤ x ≤ 0.4) films were deposited onto Si(0 0 1) or fused quartz substrates using co-evaporation of both Ge and SiO2 in high vacuum. Germanium nanocrystals were synthesized in the SiO2 matrix by furnace annealing of Gex[SiO2](1-x) films with x ≥ 0.2. According to electron microscopy and Raman spectroscopy data, the average size of the nanocrystals depends weakly on the annealing temperature (700, 800, or 900 °C) and on the Ge concentration in the films. Neither amorphous Ge clusters nor Ge nanocrystals were observed in as-deposited and annealed Ge0.1[SiO2]0.9 films. Infrared absorption spectroscopy measurements show that the studied films do not contain a noticeable amount of GeOx clusters. After annealing at 900 °C intermixing of germanium and silicon atoms was still negligible thus preventing the formation of GeSi nanocrystals. For annealed samples, we report the observation of infrared photoluminescence at low temperatures, which can be explained by exciton recombination in Ge nanocrystals. Moreover, we report strong photoluminescence in the visible range at room temperature, which is certainly due to Ge-related defect-induced radiative transitions.
AB - Ge(x)[SiO2](1-x) (0.1 ≤ x ≤ 0.4) films were deposited onto Si(0 0 1) or fused quartz substrates using co-evaporation of both Ge and SiO2 in high vacuum. Germanium nanocrystals were synthesized in the SiO2 matrix by furnace annealing of Gex[SiO2](1-x) films with x ≥ 0.2. According to electron microscopy and Raman spectroscopy data, the average size of the nanocrystals depends weakly on the annealing temperature (700, 800, or 900 °C) and on the Ge concentration in the films. Neither amorphous Ge clusters nor Ge nanocrystals were observed in as-deposited and annealed Ge0.1[SiO2]0.9 films. Infrared absorption spectroscopy measurements show that the studied films do not contain a noticeable amount of GeOx clusters. After annealing at 900 °C intermixing of germanium and silicon atoms was still negligible thus preventing the formation of GeSi nanocrystals. For annealed samples, we report the observation of infrared photoluminescence at low temperatures, which can be explained by exciton recombination in Ge nanocrystals. Moreover, we report strong photoluminescence in the visible range at room temperature, which is certainly due to Ge-related defect-induced radiative transitions.
KW - Defects
KW - Ge nanocrystals
KW - Nanoclusters
KW - Photoluminescence
KW - Raman scattering
KW - photoluminescence
KW - SILICON
KW - SIZE
KW - NANOSTRUCTURES
KW - BAND-GAP
KW - ELECTROLUMINESCENCE
KW - RAMAN-SPECTROSCOPY DATA
KW - INFRARED PHOTOLUMINESCENCE
KW - NANOCLUSTERS
KW - nanoclusters
KW - defects
KW - QUANTUM CONFINEMENT
KW - EMISSION
UR - http://www.scopus.com/inward/record.url?scp=85027143501&partnerID=8YFLogxK
U2 - 10.1088/2053-1591/aa7c38
DO - 10.1088/2053-1591/aa7c38
M3 - Article
AN - SCOPUS:85027143501
VL - 4
JO - Materials Research Express
JF - Materials Research Express
SN - 2053-1591
IS - 7
M1 - 075010
ER -
ID: 9965708