Scanning method adapted to scanning tunnel microscope

Abstract

A scanning method suitable for scanning tunneling microscopes, that is: the tunnel current is amplified by the amplifier of the measuring head to a voltage of 0-5V, converted into digital signals by a 16-bit A / D converter and sent to the computer; the computer follows the control program. Comparison operation, if it does not match, continue to adjust the displacement; if it matches, the computer sends a control signal, which is converted into 0~10V by the 20-bit D / A converter in the X direction (if the X direction scans to the maximum point position, then it is the Y direction). The voltage signal is sent to the high-voltage generator in the X direction (if the X direction scans to the maximum point position, it is the Y direction), the voltage and power are amplified by the high-voltage generator, and the amplified voltage is 0-300V, which is added to the piezoelectric On ceramics, make the probe generate a predetermined displacement in the X direction (if the X direction scans to the maximum point position, it will be the Y direction), repeat this process until the X and Y are both at the maximum value. The invention improves the imaging speed and ensures the measurement accuracy.

Description

technical field [0001] The invention relates to a scanning tunneling microscope, in particular to a scanning method suitable for the scanning tunneling microscope. Background technique [0002] Scanning tunneling microscopes can be divided into constant height method detection and constant current method detection according to different detection methods. The constant-height method is to keep the needle tip on a horizontal plane with a constant height above the sample for scanning motion, and detect the change of the tunnel current. The detection data set represents the morphology and electrical characteristics of the sample surface. A topographic image of the sample surface can be made with this data set. The constant height method has a faster test speed because it does not need to move the height of the needle tip; but it is only suitable for relatively smooth sample surfaces. The constant current method uses the feedback method to adjust ...

AI Technical Summary

Problems solved by technology

[0005] The existing scanning mode has two disadvantages. One is that when the scanner scans to a certain point, even if the tunnel current is equal to the current setting value, the scanner still has to wait for a fixed time before scanning the next point. The reason for the increase of scanning time; the second is that when the scanner scans to a certain point, if the tunnel current is not equal to the current setting value, the scanner will wait for a fixed time, regardless of whether the tunnel current value is equal to the current setting value, then proceed to the next step. A scan of a point makes the data of this point a false data

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