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Charge Transfer to LaAlO 3 /SrTiO 3 Interfaces Controlled by Surface Water Adsorption and Proton Hopping
Author(s) -
Adhikari Sanjay,
GarciaCastro Andrés C.,
Romero Aldo H.,
Lee Hyungwoo,
Lee JungWoo,
Ryu Sangwoo,
Eom ChangBeom,
Cen Cheng
Publication year - 2016
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201600820
Subject(s) - materials science , dangling bond , adsorption , chemical physics , proton , heterojunction , ion , doping , electron , nanotechnology , chemistry , optoelectronics , silicon , physics , quantum mechanics
Electronic properties of low dimensional systems are particularly sensitive to surface adsorbates. Clear understanding of such phenomena can lead to highly effective and nondestructive material engineering techniques. In this work, water adsorption at the surface of LaAlO 3 /SrTiO 3 heterostructures is systematically studied. The saturation of surface dangling bonds by spontaneous water chemisorptions is found to be a main enabler of the formation of the interface 2D electron gas. In particular, when imbalanced distributions of water based ions, namely protons and hydroxyls, are generated, interface electron doping or depletion becomes surface adsorbates dominant and independent of the LaAlO 3 layer thickness. The investigations also reveal the importance of hydrogen bonding through molecular water layers, which provides an energetically feasible pathway for manipulating the surface‐bond protons and thus the interface electrical characteristics.