We have fabricated light-emitting diodes with a transparent doping layer on silicon nanocrystals (nc-Si) embeded in silicon nitride matrix formed by plasma-enhanced chemical vapor deposition. Under forward biased condition, orange electroluminescence (EL) with its peak wavelength at about 600 nm was observed at room temperature. The peak position of the EL is very similar to that of the photoluminescence (PL) and the emitted EL intensity is proportional to the current density passing through the device. We suggest that the observed EL is originated from electron-hole pair recombination in nc-Si. By using indium tin oxide and n-type SiC layer combination as a transparent doping layer, we obtained high external quantum efficiency greater than 1.6%.
The role of the size of amorphous silicon quantum dots in the Er luminescence at 1.54 μm was investigated. As the dot size was increased, the more Er ions were located near one dot due to its large surface area and more Er ions interacted with other ones. This Er-Er interaction caused a weak photoluminescence intensity despite the increase in the effective excitation cross section. The critical dot size, needed to take advantage of the positive effect on Er luminescence, is considered to be about 2.0 nm, below which a small dot is very effective in the efficient luminescence of Er.
The role of the size of amorphous silicon quantum dots in the Er luminescence at 1.54 m was investigated. As the dot size was increased, more Er ions were located near one dot due to its large surface area and more Er ions interacted with other ones. This Er-Er interaction caused a weak photoluminescence intensity, despite the increase in the effective excitation cross section. The critical dot size needed to take advantage of the positive effect on Er luminescence is considered to be about 2.0 nm, below which a small dot is very effective in the efficient luminescence of Er. . = 0, respectively. is the decay time. The decrease in decay value with increasing dot size indicates that the nonradiative process is z
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