Modeling thermal response of Mo thin films upon single femtosecond laser irradiation: Dynamics of film melting and substrate softening

Highly Regular LIPSS on Thin Molybdenum Films: Optimization and Generic Criteria

“…The damage can be attributed to the ablation of silica being heated by molten molybdenum, whose melting temperature is much higher than that of fused silica (2897 K vs 2005 K respectively), while the recoil pressure of the ablation products forces molten material to move to the sides of the strong ablation zone [ 37 ]. Other effects that can influence the substrate deepening in the valley zones upon laser irradiation are the compaction of fused silica [ 38 , 39 ] and possibly a Marangoni convection [ 40 ].…”

“…We performed one-dimensional two-temperature modeling (TTM) for our irradiation regimes (220 nm Mo film on a glass substrate irradiated by a Gaussian laser pulse at nm and ps). The details of our numerical model are presented elsewhere [ 39 , 41 ]. Calculations were carried out for a single laser pulse action.…”

The effect of enhanced heat transfer across metal–nonmetal interfaces subject to femtosecond laser irradiation

“…This extreme situation requires the investigation of heat transfer across metal-nonmetal interfaces subject to femtosecond laser processing of thin metal films. [6][7][8][9] The typical thermal circuit between phonons and phonons across metal-nonmetal interfaces predicted by the diffuse mismatch model and the acoustic mismatch model exhibited deviation from experimental results. 10,11 Therefore, alternative thermal circuits were proposed by considering the electronphonon nonequilibrium, [12][13][14] which is a common case subject to femtosecond laser irradiation.…”

“…This extreme situation requires the investigation of heat transfer across metal–nonmetal interfaces subject to femtosecond laser processing of thin metal films. 6–9…”

“…6,7 Considering the electron-phonon nonequilibrium induced by femtosecond laser irradiation, the two-temperature model (TTM) with a metal-nonmetal interface has been widely adopted in studying the heat transfer across the metal-nonmetal interface. 9,[18][19][20] The strength of heat transfer across the metal-nonmetal interface was found to affect the melting 9,18 and ablation behavior 19 of the metal film subject to femtosecond laser irradiation. The enhancement of heat transfer across the metal-nonmetal interface by inserting an interlayer with great electron-phonon coupling strength was predicted with the TTM, 20 which was subsequently validated by experimental measurements.…”