Supporting Information Raman Signatures of Polytypism in ...
Supporting Information Raman Signatures of Polytypism in Molybdenum Disulfide Jae-Ung Lee,† Kangwon Kim,† Songhee Han,† Gyeong Hee Ryu,‡ Zonghoon Lee,‡ and Hyeonsik Cheong†,* †
Department of Physics, Sogang University, Seoul 04107, Korea
‡
School of Materials Science and Engineering, Ulsan National Institute of Science and
Technology (UNIST), Ulsan 44919, Korea
Contents: Figure S1. Crystal structures of different polytypes of 3TL-MoS2. Table S1. Space group and Raman tensors for polytypes of 3TL-MoS2. Figure S2. Large area HR-TEM images of 2H- and 3R-MoS2. Figure S3. Optical microscope images of 3R and mixed phase samples. Figure S4. Comparison of the PL spectra as a function of the number of TLs with different stacking orders. Figure S5. Peak positions of Raman modes as a function of the number of TLs with different stacking orders. Figure S6. Raman spectra of various few-layer MoS2 samples with different stacking orders.
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Figure S1. Crystall structures of differentt polytypes of 3TL-MooS2. (a-f) sidde view andd (g-l) top view.
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Table 1. Space group and Raman tensors of polytypes of 3TL-MoS2. 2H Space group Point group
Raman tensors
Shear modes
Breathing modes
3R-3
3R-4
Mixed (2H-3R)
3R-1
3R-2
No. 187, hexagonal P 6 m 2
No. 156, trigonal P3m1
D3h
C3v
a 0 0 A : 0 a 0 ; 0 0 b 0 0 0 0 0 c E : 0 0 c , 0 0 0 ; 0 c 0 c 0 0 d 0 0 0 d 0 E : 0 d 0 , d 0 0 . 0 0 0 0 0 0 Shear 2 Shear 1 (~17 cm–1) (~28 cm–1) E , Raman active, E , Raman active forbidden in backscattering Breathing 1 Breathing 2 (~28 cm–1) : (~50 cm–1) : A , Raman active
Raman inactive
a A1 : 0 0 0 E : c d
0 0 a 0; 0 b c d c 0 0 0 0 , 0 c d . 0 0 0 d 0
Shear 1 (~28 cm–1)
Shear 2 (~17 cm–1)
E, Raman active
E, Raman active
Breathing 1 (~28 cm–1) :
Breathing 2 (~50 cm–1) :
A1 , Raman active
A1 , Raman active
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M images of 3TL-MoS S2 with (a) 2H and (b) 3R stacking orders. Figure S2. Large area HR-TEM
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mixed-phasee MoS2 sam mples. The nnumber of Figure S3. Opticall microscoppe images oof 3R and m m for selected s areeas. The red rectangle inndicates thee area wheree the HR-TE EM image TLs is marked was obttained. The area of mixxed-phase M MoS2 in sam mple E is inndicated in the lower leeft image. The edgge of the mixxed phase area a and thatt of the 3R aarea make 660°.
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Figure S4. PL specctra of few--layer MoS2 with differrent stackinng orders forr thickness from 2TL m w with the exciitation energgy of 2.41 eV V. to 7TL measured
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( breathing, and (c) m main modess as a functtion of the Figure S5. Peak ppositions of (a) shear, (b) number of TLs. Sam mples with different staacking orderrs are markeed with diffferent symbools.
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Figure S6. Ramann spectra off various feew-layer M MoS2 samplees measuredd with the excitation energy oof 2.41 eV. The samplee flakes (A-G) in Fig. S S3 are indicaated. The sppectra from the mixed phase arrea of sampple E are maarked as ‘M Mixed’, wherreas the speectra with m mixed characcters from other saamples are m marked as ‘nnon-2H’.
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Department of Physics, Sogang University, Seoul 04107, Korea
‡
School of Materials Science and Engineering, Ulsan National Institute of Science and
Technology (UNIST), Ulsan 44919, Korea
Contents: Figure S1. Crystal structures of different polytypes of 3TL-MoS2. Table S1. Space group and Raman tensors for polytypes of 3TL-MoS2. Figure S2. Large area HR-TEM images of 2H- and 3R-MoS2. Figure S3. Optical microscope images of 3R and mixed phase samples. Figure S4. Comparison of the PL spectra as a function of the number of TLs with different stacking orders. Figure S5. Peak positions of Raman modes as a function of the number of TLs with different stacking orders. Figure S6. Raman spectra of various few-layer MoS2 samples with different stacking orders.
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Figure S1. Crystall structures of differentt polytypes of 3TL-MooS2. (a-f) sidde view andd (g-l) top view.
2
Table 1. Space group and Raman tensors of polytypes of 3TL-MoS2. 2H Space group Point group
Raman tensors
Shear modes
Breathing modes
3R-3
3R-4
Mixed (2H-3R)
3R-1
3R-2
No. 187, hexagonal P 6 m 2
No. 156, trigonal P3m1
D3h
C3v
a 0 0 A : 0 a 0 ; 0 0 b 0 0 0 0 0 c E : 0 0 c , 0 0 0 ; 0 c 0 c 0 0 d 0 0 0 d 0 E : 0 d 0 , d 0 0 . 0 0 0 0 0 0 Shear 2 Shear 1 (~17 cm–1) (~28 cm–1) E , Raman active, E , Raman active forbidden in backscattering Breathing 1 Breathing 2 (~28 cm–1) : (~50 cm–1) : A , Raman active
Raman inactive
a A1 : 0 0 0 E : c d
0 0 a 0; 0 b c d c 0 0 0 0 , 0 c d . 0 0 0 d 0
Shear 1 (~28 cm–1)
Shear 2 (~17 cm–1)
E, Raman active
E, Raman active
Breathing 1 (~28 cm–1) :
Breathing 2 (~50 cm–1) :
A1 , Raman active
A1 , Raman active
3
M images of 3TL-MoS S2 with (a) 2H and (b) 3R stacking orders. Figure S2. Large area HR-TEM
4
mixed-phasee MoS2 sam mples. The nnumber of Figure S3. Opticall microscoppe images oof 3R and m m for selected s areeas. The red rectangle inndicates thee area wheree the HR-TE EM image TLs is marked was obttained. The area of mixxed-phase M MoS2 in sam mple E is inndicated in the lower leeft image. The edgge of the mixxed phase area a and thatt of the 3R aarea make 660°.
5
Figure S4. PL specctra of few--layer MoS2 with differrent stackinng orders forr thickness from 2TL m w with the exciitation energgy of 2.41 eV V. to 7TL measured
6
( breathing, and (c) m main modess as a functtion of the Figure S5. Peak ppositions of (a) shear, (b) number of TLs. Sam mples with different staacking orderrs are markeed with diffferent symbools.
7
Figure S6. Ramann spectra off various feew-layer M MoS2 samplees measuredd with the excitation energy oof 2.41 eV. The samplee flakes (A-G) in Fig. S S3 are indicaated. The sppectra from the mixed phase arrea of sampple E are maarked as ‘M Mixed’, wherreas the speectra with m mixed characcters from other saamples are m marked as ‘nnon-2H’.
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