Resonance and antiresonance in Raman scattering in GaSe and InSe crystals

Abstract

The temperature effect on the Raman scattering efficiency is investigated in $$\varepsilon$$ ε -GaSe and $$\gamma$$ γ -InSe crystals. We found that varying the temperature over a broad range from 5 to 350 K permits to achieve both the resonant conditions and the antiresonance behaviour in Raman scattering of the studied materials. The resonant conditions of Raman scattering are observed at about 270 K under the 1.96 eV excitation for GaSe due to the energy proximity of the optical band gap. In the case of InSe, the resonant Raman spectra are apparent at about 50 and 270 K under correspondingly the 2.41 eV and 2.54 eV excitations as a result of the energy proximity of the so-called B transition. Interestingly, the observed resonances for both materials are followed by an antiresonance behaviour noticeable at higher temperatures than the detected resonances. The significant variations of phonon-modes intensities can be explained in terms of electron-phonon coupling and quantum interference of contributions from different points of the Brillouin zone.

The effect of temperature and excitation energy on Raman scattering in bulk HfS2

“…This offers supplementary information on the coupling of particular phonons to electronic transitions of a specific symmetry [20]. The crossover between the nonresonant and resonant conditions can be achieved not only by the variation of the excitation energy but also by the modulation of temperature [23,24]. As is seen in figures 5(a) and (b) the RS signal is enhanced significantly for the 1.96 eV and 2.21 eV.…”

“…More complicated is the description of the process in which the excited state coincides with a non-negligible density of electronic states in a process referred to as the resonant RS (RRS). The light-matter interaction in semiconductors measured by RRS can be modulated by the variation of the excitation energy and/or temperature [20][21][22][23][24][25]. The RS spectra excited with a series of lasers lines and measured at T = 300 K and T = 5 K are presented in figures 5(a) and (b), respectively.…”

Strong Influence of the Anion Radius on the Passivation of Selenium Vacancy in Monolayer InSe: Insights from Time-Domain Ab Initio Analysis

“…The peaks close to 115, 178, 196, 199, and 227 cm –1 can be assigned to the A 1 (Γ 1 2 ), E­(Γ 3 3 )/E­(Γ 3 1 )-TO (TO represents the transverse optical phonon), A 1 (Γ 1 1 )-TO, A 1 (Γ 1 1 )-LO (LO denotes the longitudinal optical phonon), and A 1 (Γ 1 3 ) modes . The peaks around 20 and 40 cm –1 can be ascribed to two in-plane phonon modes . Compared with that in pristine InSe, the numbers of the phonon modes increased in the V Se system because the Se vacancy breaks the symmetry of the In–Se lattice.…”

Tunable non-volatile memories based on 2D InSe/h-BN/GaSe heterostructures towards potential multifunctionality

“…Therefore, it is deducted that InSe is the γ -phase 22,32 and GaSe may be the ε -phase. 33,34 However, it is worth mentioning that from Raman analysis alone cannot exclusively rule out the existence of γ -phase 14 or 2H -phase 22 GaSe. In the Raman spectrum of the InSe/ h -BN/GaSe heterostructure (Fig.…”