Films minces à base de Si nanostructuré pour des cellules ...

increases for the 50 patterned sample after 4.75h-FG, whereas for the 100 patterned
sample STA leads to the highest intensity. Moreover, one can notice a blueshift of
the spectra between 4.75h-FG and STA
4.9.2 Short time annealing (STA) + Forming gas annealing
tel-00916300, version 1 - 10 Dec 2013
Since FG annealing results in emission
equivalent to STA (1min1000°C-
N 2 ) in 50 patterned ML, the next set
of investigations focussed on enhancing
the emission from STA sample by
succeeding STA with a low temperature
FG process.
Figure 4.41 compares the PL
spectra obtained from 50(3.5/5) ML
after STA+FG annealing with PL
spectra obtained from STA sample.
It can be seen from the gure that if
STA treatment is done preceding FG
annealing, it results in a detrimental
Figure 4.41: PL spectra obtained from
50(3.5/5) ML after STA + FG annealing.
eect on the emission intensity as compared to that obtained by FG annealing or
STA alone.
It is interesting to note that the PL peak position remains the same, and is
not blushifted as observed in the previous case with FG annealing. This can be
attributed to the initial STA that almost completes the reorganization of the matrix
with the formation of a high density of Si-np that would crystallize upon subsequent
annealing treatments.
4.9.3 Forming gas annealing + Short time annealing (STA)
Figure 4.42 shows the PL spectra obtained from 50(3.5/5) SRSO/SRSN ML which
was subjected to an initial annealing in FG and then succeeded by STA. The gure
also presents the spectra obtained after annealing only by STA (1min-1000 °C/N 2 ).
Since it was seen that 0.5h in FG is sucient to obtain considerable emission, such
a treatment was rst employed on SRSO/SRSN ML prior to STA treatment.
The emission intensity of 50 patterned ML annealed with 0.5h FG +STA treatment
and only 0.5h in FG are similar (ref. Fig. 4.39a). Investigations were carried
out, with varying t A under FG ow followed by STA (not shown here) and it was
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