Schematic diagram representing the observable STM topographical signal for a cantilever sample. The signal consists of a mixture of the outline of the atomic structure to be observed and movement induced by the self-oscillation. If the movement is sufficiently small, the original atomic scale structure can be rebuilt from the signal by use of a fast Fourier transformation (FFT) filter.
Expected displacement at the free end, , of a Si(111) cantilever sample induced by self-oscillation as a function of thickness. Dimensions of the sample: long and wide. Each dot represents thicknesses of 0.05, 0.10, 0.275, 0.380, 0.525, 0.750, 1.00, and .
System for the measurement of sample bending and structural observation. The detection component for sample bending consists of a cantilever sample (A), a reference electrode (B), and a clamping base (C). The additional component for structural observation consists of a cantilever sample (A) and a STM (D), which observes the effective modification area (E). Sample bending is induced by atomic scale modifications which occur only in region E.
(Color) A three-dimensional CAD image of our actual cantilever sample holder. Each color represents different materials: green, light blue, navy blue, orange, and pink correspond to super invar, quartz, cupper, and silicon, respectively.
(Color) Photograph of our developed system. This system consists of a cantilever sample holder designed by us and an Omicron UHV STM-1 (Ref. 21).
(Color) Setup for the infrared heating system. Pictures (a) and (b) display views both from above and from the front side of the cantilever sample holder, respectively. To introduce infrared light into the system via the infrared light bulb, a quartz light guide was used. The wide and narrow parts of the light guide have 20.6 and diameters, respectively. The sharp end has an off cut 30° from its cross section and the light guide stands at a 20° offset angle from the vertical direction. By use of refraction through the sharp end, the infrared light can be directed towards the effective modification area of the cantilever sample surface.
(Color online) A typical STM image of the surface taken on the cantilever sample. This image was taken with a sample bias of and a tunneling current of . The image size is . This image was scanned from left to right. The green and blue dashed lines represent cross sections along similar and different scan lines.
(Color online) Time evolution of the capacitance change. The red solid line was drawn using linear curve fitting and represents a tiny slope due to thermal drift.
(Color) Example of a simultaneous study: STM observation on a cantilever sample that detects sample bending. Graph (a) illustrates evolutions of deflections at the free end of the cantilever samples during exposure to clean surfaces at room temperature. Negative capacitance values imply that the surface is expanded from the initial condition, while positive values correspond to surface shrinkage. This illustrates compressive and tensile stress conditions, respectively. The red curve and the blue-green curve correspond to two different exposures under the same conditions. Images (b)–(d) were taken at the position indicated on the curves by the arrows. The image sizes of (b), (c), and (d) are , , and , respectively.
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