Stoichiometric transfer by infrared pulsed laser deposition of y-doped Bi–Sr–Ca–Cu–O investigated using time-resolved optical emission spectroscopy

Abstract

0.30, and 0.49 on an MgO (100) substrate was conducted using a Q-switched 1064 nm Nd:YAG laser The laser-produced plasma (LPP) emission was collected during the deposition. Time-resolved optical emission spectroscopy reveals that the plasma plume consists of neutral atoms and ions. SEM images indicate that clusters of correct stoichiometry arrive on the substrate surface. Our result confirms that IR PLD transfers material stoichiometrically. Keywords: pulsed laser deposition, plasma diagnostic techniques and instrumentation.Introduction. Pulsed laser deposition (PLD) has been extensively used in the fabrication of high-temperature superconductors such as Bi 2 Sr 2 CaCu2O 8+δ (Bi-2212) [1][2][3][4][5]. It is a flexible and straightforward technique effective in growing highly crystalline films with smooth surface morphology suitable for device applications [3,4]. Various parameters of the laser, target, and deposition conditions influence the quality of PLD films. The laser wavelength and energy density, nature of the target, and deposition time can be explored to achieve high-quality superconducting Bi-2212 films [1][2][3][4][5]. One of the challenges in PLD is the preservation of the stoichiometry between the target and the film. This was resolved recently by using an IR pulsed laser as an excitation source in fabricating Bi-2212 films [6].Most publications in PLD focus on the characterization of the films [3-8]. Only few reports are given regarding the correlation between the plasma plume and the properties of the grown film. The laser-produced plasma (LPP) formed during the ablation process provides information on the characteristics of the particles being transferred to the film [9]. Previous studies showed the effect of energy fluence from the UV laser source on the dynamics of the plasma expansion and the stoichiometry of BSCCO films [10]. One of the methods used to determine the plasma parameters is time-resolved optical emission spectroscopy. The radiation emitted by the plasma is collected, monitored, and analyzed spectroscopically during the various stages of the plasma evolution [11]. This technique is an effective way to determine the composition and other properties of the LPP [9,12,13].In this paper, we investigate the different plasma parameters of laser-produced Y-doped BSCCO plasma using time-resolved optical emission spectroscopy. The optical emission spectra were simultaneously collected with the laser deposition of Bi 2 Sr 2 Ca 1-x YxCu2O 8+δ films using a 1064 nm Q-switched Nd:YAG laser. The surface morphology, atomic composition, and transition temperature of the films with different Y concentrations were evaluated in consideration of the LPP spectra.Experimental. PLD was conducted in a vacuum chamber at a pressure of 10 -2 mbar for 180 min. The

Nanosecond and femtosecond laser deposition of BiSrCaCuO on MgO

“…Nanosecond pulses at λ= 1064 nm provide predominantly thermal excitation of the target resulting to the ejection of molten clusters toward the substrate4,15 . Without in-situ substrate heating, these ejected molten particles cools on the substrate surface as characteristic spheroidal particles4,15 . On the other hand, the presence of large clusters of particles is due aggregation of incoming deposition flux.…”

Synthesis of Iron Oxide Nanostructures via Carbothermal Reaction of Fe Microspheres Generated by Infrared Pulsed Laser Ablation

“…Herein, the deposition time was varied from 35 min (21,000 pulses) to 75 min (45,000 pulses) to control the density and size of nanoparticles on the Si(100) substrate. Since the substrate is kept at room temperature, the condensation of iron nanoparticles and microclusters aggregate on the Si substrate as spheroids, similar to our previous reports [37,38]. To grow the iron oxide nanowires/nanoflakes, the Fe microspheres were heat treated in a carbon-rich environment, as schematically shown in Figure 1b.…”

“…Previously, we reported the use of the fundamental harmonic (λ = 1064 nm) of the Nd:YAG laser for the preparation of high-temperature superconducting thin film materials. The initial morphology of the as-prepared samples is spheroidal, which crystallize and form a relatively smooth and flat film layer after high-temperature post-annealing (>850 • C) [36][37][38][39][40]. This spheroidal feature of the ablated species was observed for all types of oxide materials we investigated, suggesting that the ablated materials from the target are molten when they arrive on the substrate.…”

“…In general, to produce a thin film by PLD, the preparation condition is adjusted to decrease or suppress the droplets. More importantly, since no heat is induced on the site of arrival (usually by substrate heating), the droplets solidify, taking on a thermodynamically favored shape that in all the reported cases is spherical [36][37][38]. Previous studies also reveal that the ablation of a sintered target by an Nd:YAG laser operating at the infrared wavelength (λ = 1064 nm) produces ablation species consisting of molten-like spheroidal particles with stoichiometry resembling that of the target [36][37][38].…”

“…Since the substrate is kept at room temperature, the ablated particles solidify on the substrate layer upon cooling. Chemical analysis of the ablated species together with time-resolved optical emission spectroscopy of the laser produced plasma during infrared pulsed laser ablation showed a strong tendency of the spheroidal particles to maintain the stoichiometry of the target [37,38]. We extended the idea of using the Nd:YAG laser operating at λ = 1064 nm as the excitation source for the formation of nanoparticles on a Si(100) substrate coupled with the carbothermal reaction process to synthesize iron oxide nanostructures.…”