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In this paper we demonstrated the thermal Atomic Layer Deposition (ALD) growth at 250 {\deg}C of highly homogeneous and ultra-thin ( 3.6 nm) films with excellent insulating properties directly onto a monolayer (1L) membrane exfoliated on gold. Differently than in the case of 1L supported by a common insulating substrate (), a better nucleation process of the high-k film was observed on the 1L system since the ALD early stages. Atomic force microscopy analyses showed a surface coverage just after 10 ALD cycles, its increasing up to (after 40 cycles), and an uniform 3.6 nm film, after 80 cycles. The coverage percentage was found to be significantly reduced in the case of 2L , indicating a crucial role of the interfacial interaction between the aluminum precursor and surface. Finally, Raman spectroscopy and PL analyses provided an insight about the role played by the tensile strain and p-type doping of 1L induced by the gold substrate on the enhanced high-k nucleation of thin films. The presently shown high quality ALD growth of high-k dielectrics on large area 1L induced by the Au underlayer can be considered of wide interest for potential device applications based on this material system.
Publication date: 
21 Aug 2021

Emanuela Schilirò, Raffaella Lo Nigro, Salvatore E Panasci, Simonpietro Agnello, Marco Cannas, Franco M Gelardi, Fabrizio Roccaforte, Filippo Giannazzo

Biblio References: 
arXiv preprint arXiv:2108.09542