13:35 Aluminum metal versus aluminum oxide fabricated by nanosecond
pulsed laser deposition
Authors : Esther Rebollar1*, Mikel Sanz1, Daniel E. Martínez-Tong2, Mohamed
Oujja1, José F. Marco1, Tiberio A. Ezquerra2, Marta Castillejo1
Affiliations : 1Instituto de Química Física Rocasolano, IQFR-CSIC, Serrano
119, 28006 Madrid, Spain; 2Instituto de Estructura de la Materia, IEM-CSIC,
Serrano 121, 28006 Madrid, Spain
Resume : Pulsed laser deposition (PLD) is a versatile technique which allows
the production of thin films with tailored properties. We studied the effect of
laser fluence on the morphology, composition, structure and electric
conductivity of deposits generated by pulsed laser ablation of a metallic
aluminum target in vacuum using a Q-switched Nd:YAG laser (1064 nm, 15
JP.XI
ns). Upon irradiation for one hour at a repetition rate of 10 Hz, deposits on
65
glass consisted of smooth layers of several tens of nanometers, as revealed by
atomic force microscopy. Crystallinity, surface chemical composition and
conductivity of deposits were determined by X-ray diffraction, X-ray
photoelectron spectroscopy and broadband dielectric spectroscopy respectively.
Irradiation at fluences around 2 J/cm2, resulted in deposition of amorphous
aluminum oxide films. Differently, at higher fluences above 7 J/cm2, the
deposits are constituted by metallic aluminum films. Monitoring of the
composition and dynamics of the ablation plume was carried out by optical
emission spectroscopy which revealed differences in composition under the two
fluence regimes. In particular, highly ionized species are more abundant in the
plumes generated at higher fluences. The results are discussed by invoking the
relations between composition and dynamics of the ablation plume and the
properties of deposits, and demonstrate the possibility of control by PLD of the
properties of deposits and their either metal or dielectric character.