Comparative investigation of the vibrational properties of bulk 2H–MoS2 and its exfoliated nanosheets under high pressure

In this paper, we present a comparative study of the vibrational properties of bulk MoS2 and its exfoliated nanosheets under high pressure by resonant Raman spectroscopy. The X‐ray photoelectron spectroscopy measurements demonstrate that the nanosheets made by chemical lithium insertion method are mainly consisted of metallic 1T phase. The wavenumbers of the E2g1 and Alg Raman modes for the few layer nanosheets show a linear relationship with pressure which is different from the multilayer MoS2. This phenomenon is due to the differences in their electronic band structure. The systematic research about the 2LA (M) in bulk 2H–MoS2 suggests that the high pressure behaviour of this double resonance Raman mode arises from the pressure‐induced metallization and band gap closure. These difference vibrational properties for few and multilayer MoS2 can be applied for exploring pressure‐modulated advanced devices. Copyright © 2017 John Wiley & Sons, Ltd. We compared the vibrational properties of bulk MoS2 and exfoliated nanosheets under high pressure by resonant Raman spectroscopy. The wavenumbers of the E12g and Alg Raman modes for the few layer nanosheets show a linear relationship with pressure which is different from the multilayer MoS2. This phenomenon is due to the differences in their electronic band structure. The high pressure behaviour of the 2LA(M) in bulk 2H–MoS2 arises from the pressure‐induced metallization and band gap closure.