Electronic States and Luminescence in Porous Silicon Quantum Dots: The Role of Oxygen
Электронные состояния и люминесценция в пористых кремниевых квантовых точках: роль кислорода
1999-01-04
SCID: 54.1/w5at79sv
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photoluminescenceporous siliconquantum confinementsilicon quantum dotssurface passivation
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Abstract (AI)
Depending on the size, the photoluminescence (PL) of silicon quantum dots present in porous silicon can be tuned from the near infrared to the ultraviolet when the surface is passivated with Si-H bonds. After exposure to oxygen, the PL shifts to the red by as much as 1 eV. This shift and the changes in PL intensity and decay time, show that both quantum confinement and surface passivation determine the electronic states of silicon quantum dots. A theoretical model in which new electronic states appear in the band gap of the smaller quantum dots when a $\mathrm{Si}=\mathrm{O}$ bond is formed, is in good agreement with experiments. This result clarifies the controversy regarding the PL mechanisms in porous silicon.
Key Findings
1
A theoretical model attributes oxygen-induced behavior to new band-gap electronic states in smaller dots formed by Si=O bonds and agrees well with experiments.
2
Changes in emission demonstrate that quantum confinement and surface passivation jointly determine silicon quantum-dot electronic states.
3
Oxygen exposure shifts photoluminescence toward the red by up to 1 eV and alters both emission intensity and decay time.
4
Silicon quantum-dot photoluminescence can be tuned from near infrared to ultraviolet by varying size when surfaces are passivated with Si–H bonds.
5
The findings clarify competing explanations for photoluminescence mechanisms in porous silicon.
Research Object
silicon quantum dots in porous silicon with Si-H- or oxygen-passivated surfaces
Research Subject
the effects of quantum confinement and surface passivation, including Si=O-induced band-gap states, on the electronic states and photoluminescence
Publication Details
Publication Date
1999-01-04
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