Abstract
Although the main Raman features of semiconducting transition metal dichalcogenides are well known for the monolayer and bulk, there are important differences exhibited by few layered systems which have not been fully addressed. WSe2 samples were synthesized and ab-initio calculations carried out. We calculated phonon dispersions and Raman-active modes in layered systems: WSe2, MoSe2, WS2 and MoS2 ranging from monolayers to five-layers and the bulk. First, we confirmed that as the number of layers increase, the E′, E″ and E2g modes shift to lower frequencies, and the A′1 and A1g modes shift to higher frequencies. Second, new high frequency first order A′1 and A1g modes appear, explaining recently reported experimental data for WSe2, MoSe2 and MoS2. Third, splitting of modes around A′1 and A1g is found which explains those observed in MoSe2. Finally, exterior and interior layers possess different vibrational frequencies. Therefore, it is now possible to precisely identify few-layered STMD.
| Original language | English (US) |
|---|---|
| Article number | 4215 |
| Journal | Scientific reports |
| Volume | 4 |
| DOIs | |
| State | Published - Apr 1 2014 |
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New First Order Raman-active Modes in Few Layered Transition Metal Dichalcogenides. / Terrones, H.; Del Corro, E.; Feng, S.; Poumirol, J. M.; Rhodes, D.; Smirnov, D.; Pradhan, N. R.; Lin, Z.; Nguyen, M. A.T.; Elías, A. L.; Mallouk, T. E.; Balicas, L.; Pimenta, M. A.; Terrones, M.
In: Scientific reports, Vol. 4, 4215, 01.04.2014.Research output: Contribution to journal › Article
TY - JOUR
T1 - New First Order Raman-active Modes in Few Layered Transition Metal Dichalcogenides
AU - Terrones, H.
AU - Del Corro, E.
AU - Feng, S.
AU - Poumirol, J. M.
AU - Rhodes, D.
AU - Smirnov, D.
AU - Pradhan, N. R.
AU - Lin, Z.
AU - Nguyen, M. A.T.
AU - Elías, A. L.
AU - Mallouk, T. E.
AU - Balicas, L.
AU - Pimenta, M. A.
AU - Terrones, M.
PY - 2014/4/1
Y1 - 2014/4/1
N2 - Although the main Raman features of semiconducting transition metal dichalcogenides are well known for the monolayer and bulk, there are important differences exhibited by few layered systems which have not been fully addressed. WSe2 samples were synthesized and ab-initio calculations carried out. We calculated phonon dispersions and Raman-active modes in layered systems: WSe2, MoSe2, WS2 and MoS2 ranging from monolayers to five-layers and the bulk. First, we confirmed that as the number of layers increase, the E′, E″ and E2g modes shift to lower frequencies, and the A′1 and A1g modes shift to higher frequencies. Second, new high frequency first order A′1 and A1g modes appear, explaining recently reported experimental data for WSe2, MoSe2 and MoS2. Third, splitting of modes around A′1 and A1g is found which explains those observed in MoSe2. Finally, exterior and interior layers possess different vibrational frequencies. Therefore, it is now possible to precisely identify few-layered STMD.
AB - Although the main Raman features of semiconducting transition metal dichalcogenides are well known for the monolayer and bulk, there are important differences exhibited by few layered systems which have not been fully addressed. WSe2 samples were synthesized and ab-initio calculations carried out. We calculated phonon dispersions and Raman-active modes in layered systems: WSe2, MoSe2, WS2 and MoS2 ranging from monolayers to five-layers and the bulk. First, we confirmed that as the number of layers increase, the E′, E″ and E2g modes shift to lower frequencies, and the A′1 and A1g modes shift to higher frequencies. Second, new high frequency first order A′1 and A1g modes appear, explaining recently reported experimental data for WSe2, MoSe2 and MoS2. Third, splitting of modes around A′1 and A1g is found which explains those observed in MoSe2. Finally, exterior and interior layers possess different vibrational frequencies. Therefore, it is now possible to precisely identify few-layered STMD.
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UR - http://www.scopus.com/inward/citedby.url?scp=84926387042&partnerID=8YFLogxK
U2 - 10.1038/srep04215
DO - 10.1038/srep04215
M3 - Article
C2 - 24572993
AN - SCOPUS:84926387042
VL - 4
JO - Scientific Reports
JF - Scientific Reports
SN - 2045-2322
M1 - 4215
ER -