Seminario "Scanning Probe Microscopy operando study of the hydrogen adsorption on palladium surfaces"

DiSAT è lieta di presentare il seminario dal titolo "Scanning Probe Microscopy operando study of the hydrogen adsorption on palladium surfaces" che sarà tenuto dal prof. Luca Ottaviano del Dipartimento di Scienze Fisiche e Chimiche, Università dell'Aquila, il prossimo giovedì 27 novembre, presso la Sala Didattica alle ore 11.30

The hydrogen adsorption at room temperature on palladium (Pd) films has been studied with "operando" atomic force microscopy (AFM), Kelvin probe force microscopy (KPFM), scanning tunnel microscopy (STM), and scanning tunnel spectroscopy (STS), and backed with ancillary operando X-ray photoelectron spectroscopy (XPS).
Pd patterned films of varying thickness (15, 30, 50, 60 nm) deposited on GaAs by radio-frequency (RF) sputtering have been studied in terms of thickness and morphology with AFM (tapping mode) as a function of time and exposure to 5% H2 in nitrogen atmosphere.
The experiments demonstrate directly the swelling of the Pd film thickness of 10% of their initial height. Time- dependent operando measurements demonstrate that the phenomenon is reversible and that the film restores its initial thickness once re-exposed to pure nitrogen. The time scale of swelling and desorption is of the order of 300 s. Operando XPS however indicate that the Pd surface, once exposed to H2, undergoes a metastable transition to a Hydride phase that is stable in time and temperature. Similarly, STM/STS experiments confirm this doping effect of the Pd surface once exposed to H2.

Short bio of the speaker:

Luca Ottaviano is Full Professor of Experimental Condensed Matter Physics at the University of L’Aquila, and got his PhD in Physics in 1997. He is an experimentalist with a broad cultural background in condensed matter physics. His fields of research are surface physics and nanophysics, with multidisciplinary contaminations. Currently, he works on 2D materials beyond graphene, but he has also investigated several other systems such as 2D metals on silicon, organic semiconductor thin films, diluted magnetic semiconductors.
He has received awards and professional recognitions during his career since the early stages
His work has received more than 6000 citations and his publications amount to 183 ISI indexed papers (among which two invited reviews, two Physical Review Letters and 14 Physical Review B), two edited books (Springer), and five invited book chapters.
He has given 25 invited talks at international conferences (including a plenary) and 26 invited seminars at international institutions. He has been supervisor of 57 individual research projects with bachelor, MS, PhD and Post-Doc students. He is the inventor and Chair of international workshops and conferences (GraphX series), and has been appointed as a permanent member of several national and International Review Panels.
Fully committed in the third mission, he has organized various outreach events (among which 2 Researcher’s Nights).

Spero di incontrarvi numerosi

Dario Daghero