L46
S. Lv et al. / Journal of Alloys and Compounds 479 (2009) L43–L46
both samples is about 680 nm. A marked absorption peak appears
at 310 and 305 nm for the Cu S nanosheets (Fig. 4a) and hexagonal
2
nanoplates (Fig. 4b), respectively. The absorption shows obvious
blue shift compared to that of bulk phase (1022 nm), which arises
from a size quantum effect [6]. Additional, an absorption peak at
359 nm in Fig. 4a indicates the products on the front side have a
slightly larger crystal size and a narrower size distribution than
those on the back side [22].
4. Conclusions
In summary, Cu S with two different morphologies have been
2
synthesized, respectively on both sides of a copper foil under mild
hydrothermal conditions. This is the first time to concern the dif-
ferences of both sides of a solid substrate. It is reasonable to expect
that this simple method can be extended to fabricate other kinds of
homologous semiconductor materials for practical applications in
nanodevices.
Acknowledgement
Fig. 4. UV–vis absorption spectra of the products obtained on both sides of the
copper foil: (a) front side and (b) back side.
This work was financially supported by the National Natural
Science Foundation of China, No. 20773044.
In addition, an appropriate amount of water in the system may
oxidize the copper surface [20], so the copper substrate can also
continuously supply the copper source during the reaction. In our
hydrothermal process, the copper substrate is at the bottom of the
Teflon-lined autoclaves. For the front side of the copper substrate, a
Cu ion concentration gradient is formed from it to the bulk solution
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The UV–vis absorption spectra of the as-prepared Cu S nanos-
2
tructures are shown in Fig. 4. It is clear that the absorption edge of