Raman scattering and quantum confinement in heavily electron-irradiated alkali halides

Abstract

In this paper we will study the properties of several unusual Raman scattering peaks in heavily irradiated NaCl with vast amounts of colloidal sodium and chlorine precipitates. It appears that the laser excitation light interacts with both the electronic and vibration systems of the Na colloids, which gives rise to new Raman scattering peaks, which can be associated with electronic and vibrational excitations confined in extremely thin (about 6 nm) quantum wires. Queries for IOP paper 134075

Probing the Nanostructure of Neutron-Irradiated Diamond Using Raman Spectroscopy

“…Such behavior of the Raman spectra of crystallites under their RD has been described in the publications on electron-irradiated NaCl crystals [47], ion-implanted nanocrystals of Ge [48] and GaAs single crystals implanted with light ions [49], single crystal Si implanted with Au ions at low temperature [50], MoS 2 monolayers implanted with Mn + ions [51], and in neutron-irradiated 6H-SiC crystals [52]. Note that not all radiation-damaged materials [47][48][49][50][51][52] in which phonon confinement was observed experimentally were amorphous. The shift and the broadening of high-frequency lines of optical vibrations were observed not only in nanocrystalline and amorphous materials, but also in strongly defective materials.…”

Investigation of Inelastic Light Scattering in Heavily Electron-Irradiated Alkali Halides

“…Taking into account this change of the penetration depth we have fitted the spectra and observed an increase of the intensities of the 330 and 550 peaks (Figure 2b) with increasing volume fraction of Na-colloids. As an alternative to local phonon modes, we have explained elsewhere [7] the appearance of these peaks beyond the limits of the one-phonon spectrum of NaCl in terms of electron quantum confinement in nano-wires consisting of Na-colloids with a mean size of about 6 nm. Now we have succeeded in observing a new inelastic scattering line (at 3580 cm À1 , Figure 3) very far beyond the one-phonon cut-off frequency.…”

“…In the case of one-dimensional colloids (quantum wires along the z direction) the behavior of the confined electrons can be described by a rectangular cylindrical potential well. The spectrum of energy eigenvalues for such a quantum well looks like [7] …”

Characterization of ultra‐heavily damaged NaCl

“…transition at low temperature [1][2][3][4]. Raman scattering experiments have provided evidence for the existence of narrow quasi-1D geometrical structures of sodium nano-particles with a width of a few nm [5]. In AC conductivity measurements as a function of T we have found a discontinuity, which becomes steeper with increasing damage percentage [1].…”