Supporting Information
Photoluminescence Behavior of Plasma
Synthesized Si Nanocrystals Oxidized at Low
Temperature In Pure O2 and H2O
Stephen L. Weeks†, R.P. Chaukulkar†, P. Stradins‡*, and Sumit Agarwal†,*
† Department
of Chemical and Biological Engineering, Colorado School of Mines,
Golden, Colorado, 80401, United States
‡
National Center for Photovoltaics, National Renewable Energy Laboratory, Golden,
Colorado, 80401, United States
* Corresponding authors: sagarwal@mines.edu; pauls.stradins@nrel.gov
1
Starting surface for oxidation
Oxidation of H terminated Si nanocrystals was completed separately in O2 or
H2O vapor and the evolution of the vibrational modes during oxidation with each species
was monitored with in-situ ATR-FTIR spectroscopy. The starting surfaces of each
experiment are similar as evidenced by the absorbance change in the SiHx(x=1,2,3)
stretching region observed in the freshly deposited Si NCs shown in the inset of figure
S1. From the similarity in starting surface, it was concluded that differences observed in
surface species generated and the evolution of the Si NC photoluminescence upon
oxidation were due to the different oxidants (O2 or H2O vapor) used to oxidize the NC.
SiHx(x=1,2,3)
.02
stretching
Absorbance Change
Absorbance Change
.02
SiHx(x=2,3)
bending
2000
2050
2100
2150
-1
2200
Wavenumber cm
1000
1500
2000
2500
3000
3500
4000
-1
Wavenumber (cm )
Figure S1. Infrared absorbance spectrum for the as-synthesized H-terminated Si NCs
prior to oxidation in O2 (main figure), comparison of the SiHx(x=1,2,3) stretching
absorbance for Si NCs before oxidation in H2O (red) and O2 (black) is shown in the
inset.
2