Comparison on Morphological and Optical Properties of TiO<SUB>2</SUB> Thin Films Grown by Single-Pulse and Multi-Pulse Laser Ablation

Abstract

TiO2 thin films were prepared on glass substrates using the PLD (Pulsed Laser Deposition) technique. In order to carry out the ablation process, a Nd:YAG laser was used emitting in 1064 nm wavelength at 10 Hz repetition rate, set up for operating in both single-pulse and multi-pulse regimes. A comparison of the deposition rate, the optical and morphological properties of the layers obtained from both ablation regimes was made, which showed that the multi-pulsed ablation produced layers with a higher surface quality and better optical properties.

The Potential of Compact Libs System with Multi-Pulse Nd:YAG Laser for Bacteria Identification

“…As can be seen in Figure 2, the inter-pulse separation between the first and second pulse, and also between the second and third pulse, is about 10 microseconds. As was reported previously [12]- [14], for this inter-pulse separation a plasma reexcitation can take place, reinforcing the intensity of selected lines and them, enhancing the signal to noise relationship.…”

“…Nevertheless, their usage in lamp-pumped lasers has been more limited. In previous works, this type of saturable absorber was used in lamp-pumped lasers with high energy for applications such as thin film deposition [12].…”

Influence of laser pulse regime on the structure and optical properties of TiO2 nanolayers

“…By another way at 1064 nm with less energetic plasma, the same thermal treatment induced a transition to the anatase-brookite phase. Following our previously published analyses, it is possible to assume that the plasma was re-excited in the multi-pulse regime in the ablation process, i.e., this plasma is more energetic than that generated in the single-pulse regime, thus creating adatoms with higher energy, this could be a plausible explanation of the transition to the rutile phase with thermal treatment in the sample grown using multi-pulses [9,19].…”

“…In a previous contribution, the relation of the number of shots against the film thickness was studied [9]. It was found that multipulse regime leads to reduced growth rate and lower surface roughness, thus, in the present contribution a comparative study was conducted by growing films with similar thicknesses of ca.…”

“…In the literature, there are some papers dealing with laser ablation under multipulse excitation, those studies have shown that the splashing effect can be significantly reduced/eliminated using a second laser parallel or collinear to the target that re-excites the plasma where each laser emission was composed of multiple pulses with an interpulse separation between 10 and 100 μs [7,8]. In a recent study, some of the interactions reported by Galbacs et al were confirmed using the multi-pulse regime to deposit titanium dioxide (TiO 2 ) thin films, demonstrating that a lower deposition rate and roughness is obtained when using the multi-pulse regime for the same total emission energy, attributable to enhanced adatom mobility after plasma reexcitation [8,9]. TiO 2 is an n-type semiconductor that has emerged as an extremely valuable oxide for numerous applications because of its unique electrical and optical characteristics, in addition to being non-toxic and inexpensive [10].…”