Visible Light Emission from Si-related Nanostructures and the Effect of Ambient Atmosphere on Photoluminescence
M.-Y. Tsai, C.-C. Chi and T.-P. Perng
National Tsing Hua University, TW
Si-related nanostructures, photoluminescence, effect of ambient atmosphere
Two different types of visible light emission were observed from the Si-related nanostructures prepared by vapor condensation in an Ar-5%O2 atmosphere at various working pressures (1, 30, 50, and 100 torr). The specimen prepared at 1 torr had a nanocrystalline core sheathed by a thin oxide layer, and exhibited orange PL peaked at 800 nm in vacuum. However, the PL disappeared when air was introduced into the sample chamber. Among all the specimens fabricated at higher working pressures (30, 50, and 100 torr), an amorphous chain-like nanostructure was identified, and a blue-green light emission peaked mainly at 520 nm was observed. An effect of ambient atmosphere on the blue-green PL was also observed. After the specimen chamber was evacuated, the PL intensity increased rapidly in the beginning, and then attained a saturated value. If air was introduced into the chamber subsequently, the PL intensity increased at first in a few seconds, and exhibited an exponential decay thereafter. The mechanisms for the orange PL and the blue-green light emission from these Si-related nanostructures, and the different characteristics of PL in air and vacuum are discussed.
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Nanotech 2005 Conference Program Abstract