Rapid Laser Annealing Research Articles

Improving the conductivity of graphite-based films by rapid laser annealing.

We present a method to anneal devices based on graphite films on paper and polycarbonate substrates. The devices are created using four different methods: spray-on films, graphite pencil-drawn films, liquid-phase exfoliated graphite films, and graphite powder abrasion-applied films. We characterize the optical properties of the films before and after laser annealing and report the two-terminal resistance of the devices for increased laser power density. We find the greatest improvement (16× reduction) in the resistance of spray-on film devices starting from 25.0 kΩ and reaching 1.6 kΩ at the highest annealing power densities. These improvements are attributed to local laser ablation of binders, stabilizers, and solvent residues left in the film after fabrication. This work highlights the utility of focused laser annealing for spray-on, drawn, printed, and abrasion fabricated films on substrates sensitive to heat/thermal treatments.

Rapid laser annealing of Cu(In,Ga)Se2 thin films by using a continuous wave Nd:YAG laser (λ0= 532 nm)

Rapid laser annealing of a Cu(In,Ga)Se2 (CIGS) thin film absorber was proposed and demonstrated using a continuous 532-nm Nd:YAG laser, following sputtering with Cu0.9In0.7Ga0.3Se2 target, because the conventional annealing temperature for improving the crystallinity of CIGS thin films is higher than the decomposition temperature of a typical flexible polymer substrate. When the laser optical power was incrementally increased over the range from 2.00 to 3.00 W, for 200 s, XRD patterns showed the formation of CIGS chalcopyrite (112), (220/204), and (312/116) phases in the laser-annealed CIGS thin films, at laser optical powers of 2.75 and 3.00 W. The band gaps of these laser-annealed CIGS thin films varied from 1.45 to 1.83 eV and depended on the laser optical power. The relative mean absorbance of the laser-annealed CIGS thin films was 1.806, suggesting that approximately 98.44% of the incident photons were observed by the 600-nm-thick film in the visible spectral region. Conductivity type varied with changes in the laser optical power. The resistivities of the laser-annealed CIGS thin films were of order of 10−3 - 101 Ω-cm.

Laser annealing of electrodeposited CuInSe2semiconductor precursors: experiment and modeling

Rapid laser annealing converts CuInSe2precursors into working semiconductors only when the precursor has suitable optical and microstructural properties.

Mechanical and environmental durability of roll-to-roll printed silver nanoparticle film using a rapid laser annealing process for flexible electronics

We investigate the mechanical durability and environmental stability of laser annealed silver (Ag) nanoparticle (NP) film. Roll-to-roll printed Ag NP film on polyethylene terephthalate substrate is annealed with a rapid laser annealing process in ambient conditions as an alternative to the conventional thermal annealing process. The laser annealed Ag NP film exhibits superior electrical and mechanical properties, with fast annealing time and no damage on the substrate. The outer/inner bending test results demonstrate that the flexibility of the laser annealed Ag film is excellent. The failure bending radii in the outer/inner bending tests are 3mm. The laser annealed film can withstand 10,000 bending cycles. A nano-scratch test indicates that the adhesion strength of the laser annealed film is comparable to that of the thermal annealed film. The environmental reliability of Ag NP film is investigated under different high-temperature and high-humidity conditions, while being subjected to cyclic bending fatigue stress. The durability of printed Ag film is found to be influenced by temperature and humidity. The laser annealed film shows relatively large increase in resistance during the bending fatigue test under high temperature and humidity condition (60°C/90% RH), which is attributed to the oxidation of Ag nanoparticles and initiation of cracks. Generation of cracks is accelerated owing to the combinational effects of the cyclic stress and humidity. These results suggest that, even though the laser annealed Ag film demonstrates sufficient mechanical durability, further improvement of the film properties is required for use in extreme mechanical and environmental conditions.

Kinetics of laser induced desorption and decomposition of Fomblin Zdol on carbon overcoats

Heat assisted magnetic recording (HAMR) on magnetic hard disks is being explored as a means of increasing the areal density of stored data beyond the limits of current technologies. HAMR will subject the magnetic media, the overcoat, and the lubricant on its surface to temperatures in the range 400–650 °C for periods of a few nanoseconds per pass of the read-write head. During such rapid heating events the lubricant is prone to decomposition and desorption from the surface, either of which lead to degradation of the lubricant film, jeopardizing the integrity of the stored data. Rapid laser annealing is known to bias the reactions of small molecules adsorbed on surfaces to favor desorption over decomposition. Analysis of the desorption and decomposition kinetics of perfluoropolyalkylether lubricants such as Fomblin Zdol shows that rapid heating to high temperatures favors desorption over decomposition for molecules with molecular weights of less than 3000. For higher molecular weight Fomblins decomposition is favored at the temperatures to be used for HAMR.

Effect of ion dose rate on rapid laser annealing of implanted GaAs

Short-duration laser annealing of localized regions on P+ ion-implanted GaAs wafers has been examined for various doses and dose rates by micro-Raman scattering and Rutherford backscattering measurements. Time required for complete annealing of ion-induced defects varies from 5 ms to 1 s, corresponding to the implanted dose and rate. It is found that the amount of produced defects is enhanced by implantation with higher dose rates and that defects produced with higher dose rates are more easily annealed by the laser irradiation during short durations within a certain dose range.