Energy dispersive anti-anharmonic effect in a Fano intervened semiconductor: revealed through temperature and wavelength-dependent Raman scattering

It is always interesting to understand how the interplay between two perturbations, affects any physical process and gets manifested in a semiconductor. Temperature- and wavelength-dependent Raman Spectromicroscopy was performed on heavily-doped Si to reveal an unusual anti-anharmonic effect. Additionally, the energy dispersive behaviour of Fano coupling strength was also studied and its possible interrelation with the observed anti-anharmonic effect was explored. A systematic study revealed that at the different excitation wavelengths, the strength of the Fano interaction was different, where the involved electron-phonon (Fano-Fano-interferon) bound states were counted together with different energies. By understanding how the interplay manifests in terms of the Raman line shape, a method to calculate the Fano-interferon dissociation energy was developed. The slope of the Raman linewidth at different excitation wavelengths with temperature showed a negative temperature coefficient and sign reversal on decreasing the doping concentration. A wavelength-dependent empirical relation is proposed to calculate the required thermal energy, required to dissociate the electron-phonon bound state.

Automated summary

By performing temperature- and wavelength-dependent Raman Spectromicroscopy on heavily-doped Si, an unusual anti-anharmonic effect was discovered and its potential interrelation with the energy-dispersive behavior of Fano coupling strength was explored. A method to calculate the Fano-interferon dissociation energy was developed by understanding the manifestation of the interplay in terms of the Raman line shape, and a wavelength-dependent empirical relation was proposed to calculate the required thermal energy to dissociate the electron-phonon bound state.