Complete Report - University of New South Wales

With further optimisation of the experimental conditions, specifi cally a much thinner isolation
layer between the islands and the silicon layer, a 7 fold enhancement in the electroluminescence
and spectral response measurement has been demonstrated. Fig.4.6.5.2 shows the spectral
emission (EL) from the same SOI LED before and after island deposition.
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9
8
with Ag islands
without Ag islands
EL Signal (a.u)
7
6
5
4
3
2
1
0
900 950 1000 1050 1100 1150 1200 1250 1300
Wavelength (nm)
Figure 4.6.5.2: Electroluminescence
spectra from the same 95nm thin
SOI LED measured under identical
experimental conditions before (red)
and after (blue) deposition of the silver
islands.
The resulting EL enhancement is shown together with the SR enhancement of the same
device in Fig.4.6.5.3. The enhanced emission intensity due to surface plasmon effects is also
very clearly visible in an electroluminescence image taken with a very sensitive silicon CCD
camera (see Fig. 4.6.5.4) from a device which was partially covered with silver islands on
the left hand side. The image clearly shows the much brighter emission from that half of the
device.
Figure 4.6.5.3: Enhancement of the
spectral electroluminescence intensity
(red curve), calculated as the ratio of
the two spectra shown in Fig.4.6.5.2.
The enhancement of the photocurrent
response is shown for comparison (black
curve).
EL / Photocurrent Enhancement
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7
6
5
4
3
2
1
EL
SR
0
300 400 500 600 700 800 900 1000 1100 1200 1300
Wavelength(nm)
Figure. 4.6.5.4: Electroluminescence image of a ~ 95nm
thick 1mm x 1mm SOI LED under forward bias. The left
hand side of the device was coated with silver islands.
Clear evidence for enhanced emission from the coated
area is observed.
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