Local electrical dissipation imaged by scanning force microscopy
Local electrical dissipation imaged by scanning force microscopy
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通过扫描力显微镜成像的局部电耗散
DOI：
10.1063/1.106088
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发表时间：
1991
影响因子：
4
通讯作者：
D. Pohl
中科院分区：
文献类型：
--
作者：
W. Denk;D. Pohl
利用集成探针尖的微机械单片硅杠杆的低内部阻尼特性，可以检测探针尖与样品之间相互作用力中的非保守成分。这是通过在扫描表面时监测机械Q来实现的。间隙宽度是通过保持杠杆的共振频率失谐来控制的，这是由尖端和表面之间的力梯度引起的，固定在预设值上。即使在库仑吸引中也存在非保守分量，因为每当在尖端和衬底之间施加电压时，杠杆的振荡就会产生电流，导致能量的焦耳耗散，其速率取决于局部电导率。在层状GaAs/AlGaAs半导体异质结构中观察到强烈的阻尼对比。这取决于材料类型、掺杂剂浓度、光照和施加电压。在小于20 nm的距离上解决了阻尼变化。
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 mechanical Q while 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.