abstract

• The aim of this paper is to study the benefits of applying ultrashort pulsed lasers over nanosecond pulsed lasers for selective (i.e., superficial) heat treatment of materials in general and for selective heat treatment of thin films in particular. To this end, a background of the physics that govern the absorption of light and subsequent diffusion of heat in semiconductor and metallic materials is provided, when exposed to picosecond or nanosecond laser pulses, with a fluence below the ablation threshold. A numerical model was implemented using a commercial finite-element modeling package, to simulate the temperature fields in thin films induced by laser pulses. The results of the simulations provide insight in the temperature cycles and corresponding timescales, as function of the processing parameters, such as fluence, pulse duration, pulse repetition frequency, and laser wavelength. Numerical simulations were run for thin films of molybdenum (Mo) and zinc oxide (ZnO) on a glass substrate, which are materials commonly adopted as (back and front) electrodes in thin film solar cells. Copyright © 2016 by ASME.

authors

• De Lange Dirk Frederik
• Huis In 't Veld B.
• Römer G.R.B.E.
• Scorticati D.

publication date

• 2016-01-01

published in

• Journal of Heat Transfer  Journal

keywords

• annealing; heat transfer; modeling; molybdenum; thin films; ultrashort pulsed laser; ZnO Annealing; Finite element method; Heat transfer; Heat treatment; II-VI semiconductors; Laser ablation; Laser pulses; Models; Molybdenum; Numerical models; Oxide films; Semiconductor lasers; Substrates; Thin film solar cells; Thin films; Ultrafast lasers; Wide band gap semiconductors; Zinc oxide; Ablation thresholds; Metallic material; Nanosecond laser pulse; Nanosecond pulsed laser; Processing parameters; Pulse repetition frequencies; Temperature cycles; Ultrashort-pulsed laser; Pulsed lasers

Digital Object Identifier (DOI)

• 10.1115/1.4031733

start page

end page

volume

• 138

issue

• 3