Local electrical dissipation imaged by scanning force microscopy
作者:
Winfried Denk,
Dieter W. Pohl,
期刊:
Applied Physics Letters
(AIP Available online 1991)
卷期:
Volume 59,
issue 17
页码: 2171-2173
ISSN:0003-6951
年代: 1991
DOI:10.1063/1.106088
出版商: AIP
数据来源: AIP
摘要:
The low internal damping of micromachined monolithic silicon levers with integrated probe tip has been exploited to detect nonconservative components in the interaction forces between the probe tip and sample. This is accomplished by monitoring the mechanicalQwhile scanning the surface. The gap width was controlled by keeping the lever’s resonance frequency detuning, caused by the gradient of the force between tip and surface, fixed to a preset value. Nonconservative components are present even in Coulomb attraction since, whenever a voltage is applied between tip and substrate, currents are induced by the lever’s oscillation leading to Joule dissipation of energy at a rate that depends on the local conductivity. Strong damping contrast was observed in layered GaAs/AlGaAs semiconductor heterostructures. It depended on the type of material, dopant concentration, illumination, and the applied voltage. Damping variations were resolved over distances of less than 20 nm.
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