Plasma diagnostics in pulsed laser deposition of GaLaS chalcogenides

Abstract

The aim of this work is to characterize the ejection plume obtained by laser ablation of GaLaS (GLS) samples in order to better understand the ablation phenomena for optimizing the pulsed laser deposition of chalcogenide thin films. The dynamics of the plasma between target and substrate was investigated through timeand space-resolved optical emission spectroscopy. High-resolution optical spectra have been recorded in the UV-VIS range using a 500-mm focal length monochromator and a fast gate ICCD camera. From the space-time evolution of the optical signals, the velocities of various species (including neutrals and ions) have been derived. Using the relative intensity method, the space-and time-evolution of the excitation temperature and electronic density have been determined. A complex behavior of the laser ablation plasma has been revealed.

Laser ablation of (GeSe 2 ) 100−x (Sb 2 Se 3 ) x chalcogenide glasses: Influence of the target composition on the plasma plume dynamics

“…For our experiments the resulting glass rods (25 mm in diameter) were sliced and polished. In order to study the laser ablation process on the chalcogenide glasses the experimental set-up shown in Figure 1 was employed [24,25]. The experiments were performed in a stainless steel vacuum chamber at a residual pressure of 10 -6 Torr.…”

Experimental and Theoretical Studies on the Dynamics of Transient Plasmas Generated by Laser Ablation in Various Temporal Regimes

“…Such double-structures are often reported in the literature for both fs-and ns-laser ablation, being observed for plume propagating in an ambient gas [14,15,20,88] and in vacuum for high-fluence irradiation [56,57,67,75]. Reports from literature usually present a difference of one order of magnitude between the expansion velocities of the two plasma components.…”

“…Based on our previous ICCD fast camera imaging and space-and time-resolved optical emission spectroscopy measurements, we know that these times are characteristic for the observation of the slow plasma component [55,56,67]. As expected, it resulted that all studied parameters have a significant space-time decrease, due to the cooling process and rarefaction during expansion ( Figure 7).…”

“…From a physical perspective, fractalization implies different statistics (from Levy-type movements to Brownian movements, either by means of non-Markovian processes or Markovian ones [63,98]) that are imposed by the fundamental processes involved in the plasma formation and expansion. In such context, we assumed that generally for laser ablation there are two main mechanisms responsible for the formation and expansion of two plasma structures [15,16,56,67,73,[80][81][82], which were previously experimentally evidenced. Thus, the first structure is a result of the electrostatic interactions, at very short time scale, the positive charge left on the target surface by electron laser excitation and detachment would accelerate the positive ions outwards the surface (Coulomb mechanism [13]).…”

Rare‐earth‐incorporated low‐dimensional chalcogenides: Dry‐method syntheses and applications

“…The thickness of the above layered materials was in the micrometer scale, which was applied for the optical devices. Gurlui et al reported that the GaLaS, Er‐doped GaLaS, and Er/Pr codoped GaLaS glass thin films with the thickness in the micrometer scale have been prepared by the PLD approach (Figure ‐F). These glass films were all amorphous chalcogenides, and the increased temperature of substrate enhanced the crystallinity of the films.…”