Strain and optical characteristics analyses of three-dimentional self-ordered multilayered SiGe nanodots by photoluminescence and Raman spectroscopy

The strain state, optical properties, and band structure of the self-ordered multilayered silicon-germanium (SiGe) nanodots, which are staggered and dot-on-dot alignment and embedded by Si spacer, were evaluated by Raman spectroscopy and low-temperature photoluminescence (PL). These results suggest...

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Bibliographic Details
Published in:Japanese Journal of Applied Physics 2024-03, Vol.63 (3), p.3
Main Authors: Ito, Yuta, Yokogawa, Ryo, Wen, Wei-Chen, Yamamoto, Yuji, Minowa, Takuya, Ogura, Atsushi
Format: Article
Language:English
Subjects:
Band structure of solids
Compressive properties
dot-on-dot
Germanium
Low temperature
multilayer
nanodot
Optical properties
Photoluminescence
Raman
Raman spectroscopy
Red shift
SiGe
Silicon germanides
staggered
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Summary:The strain state, optical properties, and band structure of the self-ordered multilayered silicon-germanium (SiGe) nanodots, which are staggered and dot-on-dot alignment and embedded by Si spacer, were evaluated by Raman spectroscopy and low-temperature photoluminescence (PL). These results suggest that the compressive strain applied to the staggered nanodots is smaller than that of the dot-on-dot nanodots, which contributes to the shrinking of the bandgap of the staggered nanodots. Strong PL intensity was observed from the nanodots compared to the single crystalline bulk SiGe due to the carrier confinement and high crystal quality of the nanodots. The stack-controlled nanodots showed a redshift of the PL peaks compared to the bulk SiGe and the effect of strain induced in SiGe nanodots might not be enough to explain this phenomenon. The cause of the redshift was clarified by considering the hetero band structure of the nanodots and the tensile strained spacer.
ISSN:0021-4922
1347-4065
DOI:10.35848/1347-4065/ad231e