Light-emitting two-dimensional ultrathin silicon carbide
Supplementary Information for
Light-emitting two-dimensional ultrathin silicon carbide S. S. Lin*†‡
†
State Key Laboratory of Modern Optical Instrumentation, Department of Optical Engineering,
Zhejiang University, Hangzhou, 310027, China ‡
Manchester Centre for Mesoscience and Nanotechnology, School of Physics and Astronomy,
University of Manchester, Manchester, M13 PL, UK *
Corresponding author. Email: [email protected]
Figure S1: XRD spectra of starting wurtzite SiC powders, other than 4H-SiC, 5HSiC, 6H-SiC and a small amount of Si, no other impurities was discovered.
Figure S2: Digital photograph of SiC solutions centrifuged at a series of speeds. The SiC solutions show green-yellowish color as compared to white Boron nitride solution centrifuged at 6000 rpm and black graphene solution centrifuged at 12000 rpm.
Figure S3: Digital optical microscope image of the SiC solid paper: the centrifuged solutions were filtered through membrane with hole sizes around 200 nm and a solid paper was formed on the membrane after filtering
Figure S4: HRTEM image of small 2D SiC nanosheets on graphene substrate, where a lattice parameter of 0.26 nm can be resolved. This image shows that SiC nanosheets can be cut into small segments in a further step.
Figure S5: HRTEM image of large 2D SiC nanosheets on graphene, where a lattice parameter of 0.26 nm can be resolved. Inset: Fast Fourier transformation of red rectangular in the image, showing a six-fold lattice configuration.
Figure S6: HRTEM image of large 2D SiC nanosheets, where a lattice parameter of 0.26 nm can be resolved. Inset: Fast Fourier transformation of red rectangular in the image, showing a six-fold lattice configuration.
Figure S7: HRTEM image of large 2D SiC nanosheets, where a lattice parameter of 0.24 nm can be resolved. Inset: Fast Fourier transformation of red rectangular in the image, showing a six-fold lattice configuration.
Figure S8 A typical HRTEM image of wurtzite SiC found after the sonication process, which shows the c-lattice parameter is 1.511 nm, in agreement with that of 6H-SiC. The centrifugration process filtered most of the big crystals which remain wurtzite structure.
Figure S9 (a) AFM image of SiC solution (NMP) coated on graphene/SiO2 substrate. (b) The corresponding height profile of the line shown in Fig. S8a, indicating the height of SiC nanoflakes is typically around 0.8nm. (c)Averaged height distribution of the small nanosheet on SiO2 substrate, indicating the mean height of the nanosheets is ~0.6 nm. It should be noted the length and width of the nanosheets are usually below 50 nm, which is in accordance with the TEM observations. The AFM analysis indicates that SiC nanosheets are most possibly monolayer.
Figure S10 high-resolution XPS scan of C1s electron of sample A6K, highresolution XPS scan of Si2p is shown in the inset. C1s XPS spectra reveals the signal of wurtzite SiC and graphite SiC, locating at 283.3 eV and 284.6 eV, respectively. As the centrifugration process filtered most of the big crystals which remain wurtzite structure and most of the SiC nanosheets stand vertically to the substrate after spin-coating process, it is reasonable that the XPS spectra shown in the Fig. 4 of the manuscript does not reveals obvious signal of Si2p electron of wurtzite SiC. The 100.7eV Si2p peak is ascribed to Si-C bond. Combining Fig. S9 and Fig. 4 in the manuscript, the XPS results support the conclusion that wurtzite
SiC may be embedded under graphitic SiC. In addition to the XPS measurements, PL spectra shown in Fig. 5 also support this conclusion.
Figure S11 TEM characterization of ZnO nanosheets obtained by sonication of ZnO nanorods. (a) A typical TEM image of an ultrathin ZnO nanosheet, which is transparent to electron beams operating at 300 KV; The inset shows the selected area electron diffraction pattern, which reveals it has six-fold symmetrical structure with a lattice parameter of 0.48 nm. The lattice parameter of 0.48 nm for the a-axis
is obviously different from that of ZnO nanobelt (0.32 nm), presumably due to the graphitic structure. (b) Another typical TEM image of an ultrathin ZnO nanosheet, which is transparent to electron beams operating at 300 KV; The inset shows the selected area electron diffraction pattern, which reveals its six-fold symmetrical structure. (c) A typical TEM image of an ultrathin ZnO nanosheet.
Light-emitting two-dimensional ultrathin silicon carbide S. S. Lin*†‡
†
State Key Laboratory of Modern Optical Instrumentation, Department of Optical Engineering,
Zhejiang University, Hangzhou, 310027, China ‡
Manchester Centre for Mesoscience and Nanotechnology, School of Physics and Astronomy,
University of Manchester, Manchester, M13 PL, UK *
Corresponding author. Email: [email protected]
Figure S1: XRD spectra of starting wurtzite SiC powders, other than 4H-SiC, 5HSiC, 6H-SiC and a small amount of Si, no other impurities was discovered.
Figure S2: Digital photograph of SiC solutions centrifuged at a series of speeds. The SiC solutions show green-yellowish color as compared to white Boron nitride solution centrifuged at 6000 rpm and black graphene solution centrifuged at 12000 rpm.
Figure S3: Digital optical microscope image of the SiC solid paper: the centrifuged solutions were filtered through membrane with hole sizes around 200 nm and a solid paper was formed on the membrane after filtering
Figure S4: HRTEM image of small 2D SiC nanosheets on graphene substrate, where a lattice parameter of 0.26 nm can be resolved. This image shows that SiC nanosheets can be cut into small segments in a further step.
Figure S5: HRTEM image of large 2D SiC nanosheets on graphene, where a lattice parameter of 0.26 nm can be resolved. Inset: Fast Fourier transformation of red rectangular in the image, showing a six-fold lattice configuration.
Figure S6: HRTEM image of large 2D SiC nanosheets, where a lattice parameter of 0.26 nm can be resolved. Inset: Fast Fourier transformation of red rectangular in the image, showing a six-fold lattice configuration.
Figure S7: HRTEM image of large 2D SiC nanosheets, where a lattice parameter of 0.24 nm can be resolved. Inset: Fast Fourier transformation of red rectangular in the image, showing a six-fold lattice configuration.
Figure S8 A typical HRTEM image of wurtzite SiC found after the sonication process, which shows the c-lattice parameter is 1.511 nm, in agreement with that of 6H-SiC. The centrifugration process filtered most of the big crystals which remain wurtzite structure.
Figure S9 (a) AFM image of SiC solution (NMP) coated on graphene/SiO2 substrate. (b) The corresponding height profile of the line shown in Fig. S8a, indicating the height of SiC nanoflakes is typically around 0.8nm. (c)Averaged height distribution of the small nanosheet on SiO2 substrate, indicating the mean height of the nanosheets is ~0.6 nm. It should be noted the length and width of the nanosheets are usually below 50 nm, which is in accordance with the TEM observations. The AFM analysis indicates that SiC nanosheets are most possibly monolayer.
Figure S10 high-resolution XPS scan of C1s electron of sample A6K, highresolution XPS scan of Si2p is shown in the inset. C1s XPS spectra reveals the signal of wurtzite SiC and graphite SiC, locating at 283.3 eV and 284.6 eV, respectively. As the centrifugration process filtered most of the big crystals which remain wurtzite structure and most of the SiC nanosheets stand vertically to the substrate after spin-coating process, it is reasonable that the XPS spectra shown in the Fig. 4 of the manuscript does not reveals obvious signal of Si2p electron of wurtzite SiC. The 100.7eV Si2p peak is ascribed to Si-C bond. Combining Fig. S9 and Fig. 4 in the manuscript, the XPS results support the conclusion that wurtzite
SiC may be embedded under graphitic SiC. In addition to the XPS measurements, PL spectra shown in Fig. 5 also support this conclusion.
Figure S11 TEM characterization of ZnO nanosheets obtained by sonication of ZnO nanorods. (a) A typical TEM image of an ultrathin ZnO nanosheet, which is transparent to electron beams operating at 300 KV; The inset shows the selected area electron diffraction pattern, which reveals it has six-fold symmetrical structure with a lattice parameter of 0.48 nm. The lattice parameter of 0.48 nm for the a-axis
is obviously different from that of ZnO nanobelt (0.32 nm), presumably due to the graphitic structure. (b) Another typical TEM image of an ultrathin ZnO nanosheet, which is transparent to electron beams operating at 300 KV; The inset shows the selected area electron diffraction pattern, which reveals its six-fold symmetrical structure. (c) A typical TEM image of an ultrathin ZnO nanosheet.
