Mechanisms of resonant infrared matrix-assisted pulsed laser evaporation

Torres, Richard D., Johnson, Stephen L., Haglund, Richard F, Hwang, Jungseek, Burn, Paul. and Holloway, Paul H. (2011) Mechanisms of resonant infrared matrix-assisted pulsed laser evaporation. Critical Reviews in Solid State and Materials Sciences, 36 1: 16-45. doi:10.1080/10408436.2011.547761


Author Torres, Richard D.
Johnson, Stephen L.
Haglund, Richard F
Hwang, Jungseek
Burn, Paul.
Holloway, Paul H.
Title Mechanisms of resonant infrared matrix-assisted pulsed laser evaporation
Journal name Critical Reviews in Solid State and Materials Sciences   Check publisher's open access policy
ISSN 1040-8436
1547-6561
Publication date 2011
Sub-type Critical review of research, literature review, critical commentary
DOI 10.1080/10408436.2011.547761
Volume 36
Issue 1
Start page 16
End page 45
Total pages 30
Place of publication Philadelphia, PA, United States
Publisher Taylor and Francis
Collection year 2012
Language eng
Formatted abstract
For the last decade, a variant of pulsed laser ablation, Resonant-Infrared Matrix- Assisted Pulsed Laser Evaporation (RIR-MAPLE), has been studied as a deposition technique for organic and polymeric materials. RIR-MAPLE minimizes photochemical damage from direct interaction with the intense laser beam by encapsulating the polymer in a high infrared-absorption solvent matrix. This review critically examines the thermally-induced ablation mechanisms resulting from irradiation of cryogenic solvent matrices by a tunable free electron laser (FEL). A semi-empirical model is used to calculate temperatures as a function of time in the focal volume and determine heating rates for different resonant modes in two model solvents, based on the thermodynamics and kinetics of the phase transitions induced in the solvent matrices. Three principal ablation mechanisms are discussed, namely normal vaporization at the surface, normal boiling, and phase explosion. Normal vaporization is a highly inefficient polymer deposition mechanism as it relies on collective collisions with evaporating solvent molecules. Diffusion length calculations for heterogeneously nucleated vapor bubbles show that normal boiling is kinetically limited. During high-power pulsed-FEL irradiation, phase explosion is shown to be the most significant contribution to polymer deposition in RIR-MAPLE. Phase explosion occurs when the target is rapidly heated (108 to 1010 K/s) and the solvent matrix approaches its critical temperature. Spontaneous density stratification (spinodal decay) within the condensed metastable phase leads to rapid homogeneous nucleation of vapor bubbles. As these vapor bubbles interconnect, large pressures build up within the condensed phase, leading to target explosions and recoil-induced ejections of polymer to a near substrate. Phase explosion is a temperature (fluence) threshold-limited process, while surface evaporation can occur even at very low fluences.
Keyword Pulsed laser deposition
Solvent matrix
Phase explosion
Free electron laser
Polymers
Dendrimers
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Critical review of research, literature review, critical commentary
Collections: School of Mathematics and Physics
Official 2012 Collection
School of Chemistry and Molecular Biosciences
 
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