Nanoparticles and Thin Film Formation in Ultrashort Pulsed Laser Deposition of Vanadium Oxide

Abstract

The ultrashort pulsed laser deposition of vanadium oxide thin films has been carried out by a frequency-doubled Nd:glass laser with a pulse duration of 250 fs. The characteristics of the plasma produced by the laser−target interaction have been studied by ICCD imaging and optical emission spectroscopy. The results confirm that an emitting plasma produced by ultrashort laser pulses is formed by both a primary and a secondary component. The secondary component consists of particles with a nanometric size, and their composition and spatial angular distribution influence the deposited films. In fact, these films, analyzed by X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy, and atomic force microscopy, are formed by the aggregation of a large number of nanoparticles whose composition is explained by a model based on equilibrium thermal evaporation from particles directly ejected from the target. On these basis, the presence in the films of a mixture of V2O5 and VO2 is discussed.

Two-phase zirconium boride thin film obtained by ultra-short pulsed laser ablation of a ZrB12 target

“…In the ultra-short ablation of a large number of systems, as it is reported in literature [6][7][8]12,25], the presence of two different laser induced emissions can be distinguished: a first plasma (primary plume) lasting for few hundreds of nanosecond and characterized by the presence of electronic transitions of atomic and ionic emissions and a second one (secondary component or plume) starting after few microseconds and showing a typical black-body like emission spectrum. The emission produced by ultra-short laser ablation of the ZrB 12 target presents a particular characteristic, in fact, together with the primary and secondary plumes also a third emission of material is present.…”

“…Usually, thin films obtained by ultra-short PLD are formed by particles ranging from tens to hundreds of nanometers in diameter and no larger particles are present onto their surfaces [6][7][8]. Fig.…”

“…The expanding evaporated material is deposited on the surface of a suitable substrate to form a film. PLD is a versatile deposition technique, particularly well suited to grow thin films of a large number of materials with technological interest, such as oxides, nitrides, carbides, and borides [6][7][8][9][10]. Ultra-short PLD has been widely used for its capability to evaporate and to deposit refractory materials, transferring the target stoichiometry to the film, although the mechanism involved, in * Corresponding author.…”

Growth and characterization of Cu(In,Ga)Se2 thin films by nanosecond and femtosecond pulsed laser deposition

“…Furthermore, the existence of the (220)-oriented peak, which is beneficial for reducing the surface recombination of the CIGS absorber layer due to higher work function, is largely preserved only in films grown by the fs-PLD [13]. Preliminary studies have also shown that the relaxed structure usually accompanies with the broadened peak of (112) orientation, which is associated with high degree of structural disorder [14]. The high degree of structural disorder can be successfully suppressed for the fs-PLD CIGS thin film because of the well-crystalline characteristics confirmed by XRD spectra.…”

Synthesis of V2O3/C composites with different morphologies by a facile route and phase transition properties of the compounds

“…In the previous decades, the fabrication of V 2 O 3 was mainly focused on bulk powders and spherical particles [23,[27][28][29][30][31][32]. Recently, some techniques for preparing V 2 O 3 with a novel morphology have been reported.…”