Symmetry-dependent phonon renormalization in monolayer MoS<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow…

By B. Chakraborty, Achintya Bera, D. Muthu, S. Bhowmick, Umesh V. Waghmare, A. Sood. Physical review B, 2012

760 citations recorded by the source corpus.

A strong electron-phonon interaction which limits the electronic mobility of semiconductors can also have significant effects on phonon frequencies. The latter is the key to the use of Raman spectroscopy for nondestructive characterization of doping in graphene-based devices. Using in situ Raman scattering from a single-layer MoS2 electrochemically top-gated field-effect transistor (FET), we show softening and broadening of the A(1g) phonon with electron doping, whereas the other Raman-active E-2g(1) mode remains essentially inert. Confirming these results with first-principles density functional theory based calculations, we use group theoretical arguments to explain why the A(1g) mode specifically exhibits a strong sensitivity to electron doping. Our work opens up the use of Raman spectroscopy in probing the level of doping in single-layer MoS2-based FETs, which have a high on-off ratio and are of technological significance.

Subfields: Biomedical Engineering, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/aaa597a90c93231f6d60489cd5d8d8790877d7da

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Citations in the corpus

Thermal conductivity determination of suspended mono- and bilayer WS2 by Raman spectroscopy (2015, background): “For a 1L TMD, electrical doping causes a change of the A1g peak frequency [29], whereas the frequency of the  (1)2g E ( ) mode is found to be sensitive to strain [31, 44].”
Strong photoluminescence enhancement of MoS(2) through defect engineering and oxygen bonding. (2014, background): “26,27 A p/n-type doping would cause a blue shift/red shift of A1g peak of MoS2 due to the change of electron phonon interactions, while the E2g peak frequency is almost unaffected.(28,29) TheA1g peak of the cracked region is slightly blue-shifted by ∼1 cm 1 as”
The effect of the substrate on the Raman and photoluminescence emission of single-layer MoS2 (2013, background): “Doping is also known to affect the A1g Raman active mode [36].”
Strain-induced direct–indirect bandgap transition and phonon modulation in monolayer WS2 (2015, methodology): “Raman spectroscopy—a unique and powerful tool for investigating the layer number [42–44], stacking order [45–47], local oxidation [48], and doping effects [49, 50]—was employed with a 457-nm excitation laser line to characterize the samples before and after the transfer.”