Ultrashort Laser Induced Crystallinity in Metals Thin Films

The advances in ultrashort laser pulse (≤ picosecond) have enabled many possibilities in laser material fabrication. In laser material interactions, processes dramatically change to non-linear phenomenon when the laser pulse duration becomes extremely short, much shorter than the duration of electron–lattice relaxation processes allowing a controlled manipulation of electron dynamics without inducing the melting effects in the crystal lattice. During ultrashort laser-metal interaction, only free electrons are excited via photon–electron interactions within the pulse duration and become hot by establishing an electron temperature (Te), the lattice temperature (Tl) remains unchanged. This creates a non-equilibrium two temperature system in the material, presented by the Two-Temperature Model (TTM). The electron energy thermalization to lattice system then occurs on a picosecond timescale via electron–phonon coupling.

Ultrashort laser pulses can enable a transformative impact on materials processing which cannot be achieved with short and long pulse lasers and other thermal methods. The opportunity to enable selective laser crystallization of thin film materials on a variety of substrates, particularly heat sensitive, flexible materials without creating large heat affected zones (HAZ) and with minimal thermal effects is crucial for conductive electronic thin film applications. Ultrashort laser crystallized thin films at low fluences, below the melting threshold, exhibit improved large grain sizes and improved electronic transport, influencing the overall electrical properties of metal crystal lattice. However, it is challenging to selectively crystallize high melting temperature metal thin film on a substrate with a comparatively lower melting temperature because the heat generated during laser scanning can undesirably damage or melt the nearby areas/components. Therefore, enabling precisely controlled and low fluence processes in ultrashort pulse regime is promising to address the problems associated with high processing temperature and HAZ.

This special topic invites authors to contribute their original research by submitting full research articles, letters, and possibly reviews focusing on non-thermal laser crystallization of metal thin films on thin, flexible substrates by using ultrashort laser pulses. The authors are encouraged to probe and support their results by outlining the physics of ultrashort laser material interaction and the origin of non-thermal crystallization in metal thin films. This special issue will offer a platform for disseminating key information of ultrashort laser induced crystallinity particularly in metal thin films, synthesis procedures, fabrication, and metrologies.

The manuscript should put emphasis on laser induced crystallization including the topics/key words listed below.

Topics covered include, but are not limited to:

Guest Editors

Ayesha Sharif, University of Galway

Submission Instructions

For those interested in submitting, please take note of the following instructions:

1. Navigate to the journal’s online submission system: https://jla.peerx-press.org/cgi-bin/main.plex. You may need to create an account if you do not already have one.
2. During the submission process you will be asked if your manuscript is part of a special topic. Please answer “yes” and select “Ultrashort Laser Induced Crystallinity in Metals Thin Films” from the subsequent drop-down menu.

Papers that are accepted for publication will publish immediately upon acceptance and will appear online in a virtual collection dedicated to this special topic. Any questions or concerns about the submission process or deadline should be directed to the Journal of Laser Applications journal manager at jla-journalmanager@aip.org.