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Probing the Domain Architecture in 2D α‐Mo 2 C via Polarized Raman Spectroscopy
Author(s) -
Li Tianshu,
Luo Weijun,
Kitadai Hikari,
Wang Xingzhi,
Ling Xi
Publication year - 2019
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201807160
Subject(s) - raman spectroscopy , materials science , spectroscopy , phonon , anisotropy , density functional theory , chemical vapor deposition , crystallography , nanotechnology , condensed matter physics , optics , computational chemistry , chemistry , physics , quantum mechanics
MXenes are emerging 2D materials with intriguing properties such as excellent stability and high conductivity. Here, a systematic study on the Raman spectra of 2D α‐Mo 2 C (molybdenum carbide), a promising member in MXene family, is conducted. Six experimentally observed Raman modes from ultrathin α‐Mo 2 C crystal are first assigned with the assistance of phonon dispersion calculated from density functional theory. Angle‐resolved polarized Raman spectroscopy indicates the anisotropy of α‐Mo 2 C in the b – c plane. Raman spectroscopy is further used to study the unique domain structures of 2D α‐Mo 2 C crystals grown by chemical vapor deposition. A Raman mapping investigation suggests that most of the α‐Mo 2 C flakes contain multiple domains and the c ‐axes of neighboring domains tend to form a 60° or 120° angle, due to the weak MoC bonds in this interstitial carbide and the low formation energy of the carbon chains along three equivalent directions. This study demonstrates that polarized Raman spectroscopy is a powerful and effective way to characterize the domain structures in α‐Mo 2 C, which will facilitate the further exploration of the domain‐structure‐related properties and potential applications of α‐Mo 2 C.