Experimental evidence of the “dead layer” at Pt∕BaTiO3 interface

Abstract

The Pt∕BaTiO3 (BTO) interface was investigated by angle-resolved x-ray photoelectron spectroscopy and x-ray reflectivity technique. It was shown that there exists a transition layer of about 9Å at the Pt/BTO interface with electron density lower than that of the BTO film. The transition layer shows a higher binding energy of Ba 3d than that of the bulk BTO. Moreover, neither the interdiffusion of BTO and Pt nor the oxidation of Pt near the interface had been observed. We consider that this layer is caused by “interface-induced relaxation.” This relaxation layer is believed to be the origin of the “dead layer” effect.

Characterization of non-stoichiometric co-sputtered Ba0.6Sr0.4(Ti1 − x Fe x )1 + x O3 − δ thin films for tunable passive microwave applications

“…The origin of the Ba4d doublet at higher binding energy (Ba 4 d 5/2 =89.6 eV) is discussed controversially in literature as a topmost thin barium oxide [29] or barium carbonate layer [27], or as a surface relaxation of the crystal structure [30,31]. Due to the C1s and O1s photoelectron peaks at 288.6 and 530.7 eV, respectively, which are related to carbonate binding energies [32][33][34], the BaCO 3 formation is justified.…”

Interface electronic structure in a metal/ferroelectric heterostructure under applied bias

“…The Ba 3d 5/2 spectrum has a high-binding-energy (HBE) component often attributed to under-coordinated barium at the surface for BaO termination. [21][22][23] However, for a TiO 2 -terminated surface, this is erroneous. The topmost Ba atoms are in the first layer below the surface and are fully oxygen coordinated, therefore we do not expect a surface peak due to under-coordinated Ba.…”

Compounds and Nanocomposites: Hetero-Coordination

“…The higher density persists disregarding the thickness of the layered films [55]. The charge density in the Pt/BaTiO 3 interface dead layer region is about 10 % higher than the bulk because of the lattice strain [56]. A dead layer of 3 nm thick has also been found in the Ba 0.7 Sr 0.3 TiO 3 /SrRuO 3 interface [57].…”