Nontrivial Raman Characteristics in 2D Non-Van der Waals Mo5N6
Journal
ACS Nano
Journal Volume
18
Journal Issue
47
Start Page
32458
End Page
32467
ISSN
19360851
1936086X
Date Issued
2024
Author(s)
Yao, Chinghsiang
Gao, Hongze
Ping, Lu
Gulo, Desman Perdamaian
Liu, Hsianglin
Saito, Riichiro
Ling, Xi
Abstract
Resonant Raman spectra of a two-dimensional (2D) non-van der Waals (vdW) material, molybdenum nitride (Mo5N6), are measured across varying thicknesses, ranging from a few to tens of nanometers. Fifteen distinct Raman peaks are observed experimentally, and their assignments are made using first-principles calculations for the most stable AABB-stacking structure of Mo5N6. The assignments are further supported by angular-dependent Raman measurements for all peaks, except the most intense one at 215 cm-1. Calculations reveal that the 215 cm-1 peak does not appear for three-dimensional molybdenum nitrides and is not a first-order Raman-active mode. We further investigated the origin of the 215 cm-1 peak and assigned it as a defect-induced double-resonance peak. Moreover, thickness-dependent Raman measurements reveal that both the 215 and 540 cm-1 peaks─assigned to out-of-plane and in-plane modes, respectively─blue shift as thickness increases, reaching a plateau around 20 nm. This thickness-dependent Raman shift over a wide thickness range is nontrivial compared to other common vdW 2D materials and is attributed to the much stronger stacking interaction between the constituent layers in non-vdW materials. This finding highlights Raman spectroscopy as a valuable tool for characterizing the thickness of 2D non-vdW materials.
Subjects
Brite-wigner-fano (bwf)
Defect-induced Peak
Metal Nitrides
Resonant Raman
Thickness Dependence
Two-dimensional Materials
Molybdenum
Aluminum Nitride
Defects
Iii-v Semiconductors
Indium Phosphide
Layered Semiconductors
Molybdenum Compounds
Nickel Compounds
Nitrides
Raman Spectroscopy
Brite-wigne-fano
Defect-induced Peak
Defects Induced
Metal Nitrides
Molybdenum Nitride
Resonant Raman
Thickness Dependence
Two-dimensional
Two-dimensional Materials
Van Der Waal
Van Der Waals Forces
Molybdenum
Article
Controlled Study
Pharmaceutics
Raman Spectrometry
Thickness
Publisher
American Chemical Society
Type
journal article