Open AccessProbing timescales during back side ablation of Molybdenum thin films with optical and electrical measurement techniques
Author(s) -
Dominik Bartl,
M. Ametowobla,
Florian Schmid,
Andreas Letsch,
Matthias Häfner,
Stefan Nolte,
Andreas Tünnermann
Publication year - 2013
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.21.016431
Subject(s) - materials science , optics , fluence , ablation , laser ablation , molybdenum , laser , photovoltaics , electrical conductor , thin film , substrate (aquarium) , optoelectronics , composite material , nanotechnology , photovoltaic system , physics , ecology , oceanography , aerospace engineering , geology , metallurgy , biology , engineering
In this study we present a new measurement technique to investigate the timescales of back side ablation of conductive films, using Molybdenum as an application example from photovoltaics. With ultrashort laser pulses at fluences below 0.6 J/cm(2), we ablate the Mo film in the shape of a fully intact Mo 'disc' from a transparent substrate. By monitoring the time-dependent current flow across a specifically developed test structure, we determine the time required for the lift-off of the disc. This value decreases with increasing laser fluence down to a minimum of 21 ± 2 ns. Furthermore, we record trajectories of the discs using a shadowgraphic setup. Ablated discs escape with a maximum velocity of 150 ± 5 m/s whereas droplets of Mo forming at the center of the disc can reach velocities up to 710 ± 11 m/s.