Publications by authors named "En-De Chu"

A localized Zeeman field, intensified at heterostructure interfaces, could play a crucial role in a broad area including spintronics and unconventional superconductors. Conventionally, the generation of a local Zeeman field is achieved through magnetic exchange coupling with a magnetic material. However, magnetic elements often introduce defects, which could weaken or destroy superconductivity.

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Control of work function (WF) in graphene is crucial for graphene application in electrode material replacement and electrode surface protection in optoelectronic devices. Although efforts have been made to manipulate the effective WF of graphene to optimize its application, most studies have focused on graphene employed in static electrical contact interfaces. In this work, we investigated WF variations of supported single-layer graphene (SLG) in sliding electrical contact under ambient conditions, which was achieved by sliding an electrically biased conductive atomic force microscopy (cAFM) probe on the SLG surface.

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We have investigated the frictional properties of single-layer graphene (SLG) coated rough silica substrate under the influence of nano-confined hydration layer underneath SLG. Through the friction and surface potential measurements by atomic force microscopy (AFM), we found polygonal features in AFM images of SLG-protected silica surface that exhibit simultaneously larger friction and higher surface potential as compared to their surrounding areas due to water layers confined under SLG. Nano-confined water layers at the SLG-silica interface can induce the hole-doping effect in SLG, resulting in a more positively-charged and hydrophilic surface that favors adsorption of ambient water molecules.

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Oxygen vacancy is the most studied point defect and has been found to significantly influence the physical properties of zinc oxide (ZnO). By using atomic force microscopy (AFM), we show that the frictional properties on the ZnO surface at the nanoscale greatly depend on the amount of oxygen vacancies present in the surface layer and the ambient humidity. The photocatalytic effect (PCE) is used to qualitatively control the amount of oxygen vacancies in the surface layer of ZnO and reversibly switch the surface wettability between hydrophobic and superhydrophilic states.

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