Research lines

In pulsed laser deposition (PLD) the material ejected in the ablation plume is deposited on a substrate placed in front of the target as shown in the scheme of the typical set up.

PLD provides a method of depositing thin coatings and nanostructured deposits, of a wide range of target materials, on different substrates. We focus on the understanding of the mechanisms of laser-target interaction, on the characterization of the properties and dynamics of the ablation plume and on physicochemical characterization of deposits (morphology, composition, structure). To this purpose we use different techniques including scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, X-ray diffraction and micro-Raman spectroscopy.

Simultaneously to the PLD, the ablation plume can be characterized by optical emission spectroscopy.

                                                                                      

                                                            PLD set-up                                                                                         Image of ablation plume inside PLD chamber                                                                                                                                                                                                      

 

References

M. Walczak et al., Appl. Surf. Sci. 255, 5267 (2009).

M. Sanz et al., J. Phys. Chem. C 115, 3203 (2010).

M. Sanz et al. Appl. Surf. Sci. 282, 642-651 (2013).

M. Jadraque et al. J. Phys. Chem. C. 117, 5416–5423 (2013). 

M. Monti et al J. Appl. Phys. 114, 223902 (1-5) (2013).

I. Lopez-Quintas et al. Appl. Surf. Sci. 328, 170-176 (2015).

J. de la Figuera et al. Appl. Surf. Sci. 359, 480-485 (2015).

J. de la Figuera et al. Croat. Chem. Acta  88(4), 453-460 (2015).

L. Martín-García et al. J. Mater. Chem. C  4, 1850-1859 (2016). 

  

Contact: This email address is being protected from spambots. You need JavaScript enabled to view it., This email address is being protected from spambots. You need JavaScript enabled to view it.This email address is being protected from spambots. You need JavaScript enabled to view it.

  

Femtosecond Pulsed Laser Deposition (fs-PLD) is a versatile technique for the fabrication of metal and semiconductor nanoparticles due to the possibilities it offers to control size and shape of nanodeposits by varying the laser parameters. Various studies have shown the possibility of using fs PLD as a general route to nanoparticle formation and have demonstrated that the nature of nanostructured deposits grown by fs-PLD strongly depends on the material and deposition conditions.

An example of such degree of controlled PLD can be seen in the following image, where nanostructured CdS films were fabricated in our group by fs-PLD at different laser wavelengths. The image below shows that the smallest nanoparticles, with an average diameter < 20 nm and a narrow size distribution, are obtained through UV fs-PLD. At longer wavelengths, deposits show structures with larger typical sizes. 

 

ESEM images of the surfaces of TiO2 thin films grown at the indicated deposition conditions

 

Another ingredient of control allowed by fs-PLD is the used of temporally tailored laser pulses. The simplest case is the use of sequences of two pulses, with control of their relative arrival times to the target, as well as their individual pulse energies. The scheme below shows the setup designed by our group and installed in the CLUR (Center for Ultrafast Lasers, UCM, Madrid) for double-pulse fs-PLD.

 

fs PLD set-up with temporally tailored laser pulses

References

M. Sanz et al., Appl. Surf. Sci. 255, 5206 (2009).

M. Sanz et al., Appl. Phys. A 101, 639-644 (2010). 

M. Sanz et al., J. Phys. Chem. C 115, 3203 (2011).

M. Jadraque et al. J. Phys. Chem. C. 117, 5416–5423 (2013). 

I. Lopez-Quintas et al., Phys. Chem. Chem. Phys. 18, 3522 (2016).

  

Contact: This email address is being protected from spambots. You need JavaScript enabled to view it., This email address is being protected from spambots. You need JavaScript enabled to view it.This email address is being protected from spambots. You need JavaScript enabled to view it.

 

Laser induced forward transfer (LIFT) is a deposition method in which a pulsed laser beam is focused through a transparent support onto a thin film of the material to be transferred. Under laser irradiation, a micrometer sized droplet of film material is ejected and transported onto a receptor surface placed nearby. This method allows the fabrication of a customer defined pattern with a high lateral resolution onto any substrate of a broad range of materials.

SEM images of laser induced forward transferred TiO2 at 248 nm FTO coated glass at 2 nJ 

Contact: This email address is being protected from spambots. You need JavaScript enabled to view it.This email address is being protected from spambots. You need JavaScript enabled to view it.

 

Pulsed laser ablation of solids in liquid environments (PLAL) can be used as a technique for the fabrication of nanoparticles (NPs) of a large variety of materials including metals, alloys, ceramics, and semiconductors. Remarkable advantages of this method over chemical synthesis rely on the simplicity of the procedure, the weak agglomeration effects, and the lack of impurities caused by chemical precursors.

The concentration, size, polydispersity, shape and solid phase (amorphous or crystalline) of nanoparticles fabricated by PLAL can be controlled by the adequate choice of laser wavelength, pulse duration, and fluence and by the use of stabilizing agents of different crystallinity and molecular weight. To this purpose the optical properties of the colloidal solutions are investigated by UV-vis absorption spectroscopy, whereas the size, morphology and structure of the nanoparticles are characterized by transmission electron microscopy (TEM) and high resolution TEM (HRTEM).

 PLAL set-up

 

Platinum nanoparticles fabricated by UV ns PLAL

 

Contact: This email address is being protected from spambots. You need JavaScript enabled to view it.This email address is being protected from spambots. You need JavaScript enabled to view it. This email address is being protected from spambots. You need JavaScript enabled to view it.