Surface Texturing of Polyethylene Terephthalate Induced by Excimer Laser in Silver Nanoparticle Colloids

We report on a novel technique of surface texturing of polyethylene terephthalate (PET) foil in the presence of silver nanoparticles (AgNPs). This approach provides a variable surface morphology of PET evenly decorated with AgNPs. Surface texturing occurred in silver nanoparticle colloids of different concentrations under the action of pulse excimer laser. Surface morphology of PET immobilized with AgNPs was observed by AFM and FEGSEM. Atomic concentration of silver was determined by XPS. A presented concentration-controlled procedure of surface texturing of PET in the presence of silver colloids leads to a highly nanoparticle-enriched polymer surface with a variable morphology and uniform nanoparticle distribution.

Increasing Laser-Doping Depth of Al in 4H-SiC by Using Expanded-Pulse Excimer Laser

Al doping into 4H-SiC performed by irradiating pulse-width-expanded excimer laser to an Al film deposited on the 4H-SiC surface is investigated. An optical pulse stretcher was constructed to produce the laser pulse whose peak intensity was reduced as half as that of the original pulse and pulse width was expanded from 55 ns to 100 ns. The irradiation of the expanded pulses is found to reduce the ablation of the materials from the surface and enable irradiation of multiple shots. As the result, doping depth of Al is significantly increased. The multiple shots of the expanded pulses is also fund to decrease the sensitivity to spatial non-uniformity of laser intensity and increase the uniformity of doped region.

Al Doping from Laser Irradiated Al Film Deposited on 4H-SiC

Al doping of 4H-SiC with high surface concentration and deep depth profile is found to be realized by irradiating single-pulse excimer laser to an Al film deposited on the surface. Optical emission spectra suggest that high-temperature molten Al is produced behind the laser-generated high-density Al plasma and Al is diffused from the molten Al into 4H-SiC. The Al doping depth reaches to ~200 nm by irradiating a single laser pulse. A pn junction diode fabricated by the doping with the molten Al shows on/off ratio over 10 orders of magnitude.

Pulse-Laser-Crystallization of Amorphous Nd3.7Pr3.4Dy0.9Fe86B5Nb1

The pulse-laser-crystallization (PLC) technique was applied to Nd3.7Pr3.4Dy0.9Fe86B5Nb1 amorphous ribbons. After irradiation with a 248nm KrF pulse excimer laser at a fequency of 15Hz for 1 min, the Nd3.7Pr3.4Dy0.9Fe86B5Nb1 amorphous ribbons crystallized into the homogeneous Nd2Fe14B/α-Fe nanocomposite permanent magnetic materials with an average grain size around 26nm. The obtained coercivity, remanence, and (BH)max values were 6.6 K, 1.23 T, and 18.5 MGOe, respectively.