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24

The sample holder is now moved towards the tip with the help of the piezo
motor, until the tunneling current entered under ‘SetPoint’ is detected. Now
the distance between sample and tip is controlled by the feedback loop. If
the approach was successful, the LED on the scan head changes from or-
ange to green and the message box ‘Approach done’ appears.

- Click the ‘OK’-button.

Now the set tunneling current is flowing between tip and sample.
When the LED changes to red instead of green, the sample has ‘crashed’
into the tip, and the tip has to be cut again. (See chapter Problems and
Solutions
).

Start measurement

When the tunneling current defined by ‘SetPoint’ is flowing between tip
and sample (LED green) you can start measuring:

- Click 

 in the ‘Scan Panel’ to maximize the range of the scan.

- Start measuring by clicking 

 in the ‘Scan Panel’.

If the preparation of tip and sample, and the approach were successful,
images of the measurement will show a line in the ‘LineView’ (figure start-
ing picture, left
) and a plane in the ‘TopView’. Watch the displays for a while
until the ‘TopView’-image has been drawn about three times.
A ‘nervous’ line in the ‘LineView’ indicates a bad tunneling contact (figure
starting picture, right). Usually this is caused by the tip being too blunt or
instable. This means that you should stop measuring and cut a new tip:

- Click 

 and follow the instructions of the chapter Problems and Solu-

tions.

F

IRST

 M

EASUREMENTS

S

TART

 

MEASUREMENT

Summary of Contents for easyScan E-STM

Page 1: ...1 Operating Instructions easyScan E STM Version 2 1...

Page 2: ...2 NANOSURF AND THE NANOSURF LOGO ARE TRADEMARKS OF NANOSURF AG REGISTERED AND OR OTHERWISE PROTECTED IN VARIOUS COUNTRIES JANUARY 2004 BY NANOSURF AG SWITZERLAND PROD BT00655 V2 1R1...

Page 3: ...ling the sample 19 First Measurements 20 Starting the microscope 20 Approaching the tip 21 1 Coarse approach by hand 21 2 Fine approach by piezo motor 22 3 Automatic approach 23 Start measurement 24 A...

Page 4: ...opy is one of the most exciting scientific techniques The insight into small dimensions has led to a new understanding of the structure of materials and forms of life With the help of the scanning tun...

Page 5: ...ring that the size of the atom in relation to the tip is that of a golf ball to a mountain Scanning with the E STM In the E STM a platinum iridium tip is moved in three dimensions using piezo crystal...

Page 6: ...sible to measure the tip sample movement very precisely One of the three piezo crystals the z piezo can now be used in a feedback loop that keeps the tunneling cur rent constant by appropriately chang...

Page 7: ...use the tip would otherwise crash in to the sample What is so special about the Nanosurf easyScan E STM The E STM was designed to allow people without training as a physicist to do experiments in the...

Page 8: ...se free Never touch either the wire for tips figure components 8 e the sample 8 g nor the open part of the STM scan head 2 with your fingers Only touch the sample holder 8 f at the black plastic end U...

Page 9: ...aining the easyScan E Line software this manual software reference manual a test sheet and a sheet with the calibration information a Case for storing and transporting the instrument Additionally the...

Page 10: ...he easyScan E SPM electronics 1 Make sure your computer is turned off Then connect the control elec tronics to a free serial port or RS232 or COM Port on your computer with the RS232 cable 4 If you ar...

Page 11: ...Adapter ES option must be acquired to use the USB port Installation Procedure Turn on your computer and start Windows Do not run any other program while installing the scan software If you are using...

Page 12: ...which the program files are to be copied Put them in the proposed directory unless the Program Files directory has a different name in your language of the Windows operating system Afterwards setup wi...

Page 13: ...ion figure components 1 The setup program will start copying files onto your hard disk After successful installation you will get this confirmation Important The E Line software CD delivered with the...

Page 14: ...he following dialog box appears By clicking Start Simulation a simulation of the microscope is started This imitates most of the functions of the real microscope The sample is replaced by a mathematic...

Page 15: ...tting part of the wire cutters figure components 8 a the half round pliers 8 b and the pointed tweezers 8 c have been cleaned with ethanol Touch the Pt Ir wire 8 e with these tools only hold the end o...

Page 16: ...n your scan head Single clamp see figure Mounting the tip under the single clamp a b 2 1 Mounting the tip under the single clamp 1 Put the tip wire on the tip holder parallel to the groove in the tip...

Page 17: ...t clamp figure b 3 Push the wire in until it touches the second clamp 4 Lift the wire 5 Push the end of the wire below the second clamp 6 Lower the wire so that it lifts the second clamp figure c 7 Pu...

Page 18: ...o the layered structure of graphite this can easily be done using a piece of adhesive tape see pictures below Put the sample on the table using the pair of tweezers Stick a piece of adhesive tape gent...

Page 19: ...ng only its black plastic handle Put the prepared sample onto the magnetic end of the sample holder using a pair of tweezers See below Place the sample holder carefully in the scan head so that it doe...

Page 20: ...This damages the end of the tip and it has to be cut again Starting the microscope The red LED of the E SPM electronics 1 should now be flashing when the easyScan E Line software has not been started...

Page 21: ...the tip and the sample LED orange z piezo fully extended toward the sample the distance is too big not tunneling current can be detected LED red z piezo fully retracted The tip touched or crashed into...

Page 22: ...mal drift in measurements at atomic scale 2 Fine approach by piezo motor Open the Panels menu in the easyScan E Line program window Select the Approach Panel Watch the distance between tip and sample...

Page 23: ...using the up and down arrow keys on the keyboard The new value is automati cally used after one second The value of a numerical input can also be increased and decreased by clicking the arrow buttons...

Page 24: ...unneling current defined by SetPoint is flowing between tip and sample LED green you can start measuring Click in the Scan Panel to maximize the range of the scan Start measuring by clicking in the Sc...

Page 25: ...y the plane of the measurement and the sample s surface should lie in the x y plane of the scanner But mostly the sample plane is tilted with respect to that ideal plane In this case the sample cross...

Page 26: ...he values of X Slope and Y Slope You can align the measurement plane with the sample plane using the fol lowing procedure Alter the value of X Slope using the arrow buttons until the x axis of the sca...

Page 27: ...ignals amplified in order to observe the atomic struc ture Reminder Measurements on the nanometer scale are very sensitive Direct light fast movements causing air flow and temperature variations near...

Page 28: ...zoom function by clicking with the right mouse button 3 Atomic arrangements can normally be made out at a ScanRange of about 4 nm and at a Z Range of about 1 5 nm Enter these values in Scan Panel one...

Page 29: ...ine in the ScanPanel to 0 06s for atomic resolution View Panel If the contrast in the Top View window is too large or too small open the View Panel see figure and select in the Visible Input Range sec...

Page 30: ...constant by the feedback loop and the movements of the tip by the z piezo are re corded This height profile is displayed in a LineView and the topo graphic image is displayed as a grey scale coded Top...

Page 31: ...d A good tunneling contact is necessary for high quality images of atomic resolution If temperature variations are present they cause so called thermal drift Consequently the images are stretched This...

Page 32: ...ems and solutions Image quality suddenly deteriorates In the following cases the tip has to be replaced i e cut freshly in order to establish a stable tunneling contact and high image quality If image...

Page 33: ...the image correctly you must first be aware that bright spots show high points and dark spots low ones except in LineMath Derive In the lattice model of graphite one can see that there are two differe...

Page 34: ...ve the higher than normal value of 0 25nm Measuring Gold It is more difficult to obtain good images of a gold Atomic structures are difficult to observe because the electrons on the surface are much m...

Page 35: ...eptions to note select a gap voltage between 0 3 0 5V increase the value of parameter Time Line to 0 3s in the Scan Panel If you do not get stably reproduced scan lines you should look for another cle...

Page 36: ...see also Software Reference Turning off and storing the instrument Exit the easyScan E Line program after having stored all desired images If you leave the program without saving some data the program...

Page 37: ...still blue see chapter maintenance By storing the instrument in the suitcase it is protected from dust Simulta neously the rubber feet of the vibration isolation platform should be re lieved The dampi...

Page 38: ...he sample holder must be stored in its container together with the moisture absorbing silica container The container is waterproof but not airtight The silica contains a blue indicator which turns pin...

Page 39: ...der with a cotton swab if necessary lightly moistened with alcohol ensure the tip is removed when doing this Scan electronics Clean the cabinet and the controls with a soft cloth lightly moistened wit...

Page 40: ...s is not connected to the power supply check that the power LEDs on the electronics are on check the connection The easyScan SPM electronics is not connected to the computer check the connection The w...

Page 41: ...pen the Approach Panel s extended configuration using Increase the value of Stepsize and click Now the motor moves the sample holder with larger steps during automatic approach Save the new value for...

Page 42: ...ts old value again Retract the sample using then perform a new approach If no improvement can be seen after going through these procedures you have to prepare a new tip Did the scan line in the LineVi...

Page 43: ...suring graphite Z Offset does not change automatically In the default configuration of the easyScan E Line software the item in menu Options Auto Adjust Z Offset is activated If the numeric value of Z...

Page 44: ...can range typ 0 5 m 1 m optional Maximum Z range 200 nm Drive resolution Z 0 003 nm Drive resolution XY 0 015 nm gap voltage 10V in 5mV steps Set point current 100nA in 25pA steps sample size max 10mm...

Page 45: ...an Z Feedback Approach Spectroscopy RS232 Host PC RAM ROM 3 16 Bit DAC 10V 10V Optional 16Bit DAC Z Approach 3 16 Bit DAC 16 Bit DAC 12V Piezo Scanner X Y Z Axis 12 Bit DAC 12V Approach speed 16 Bit D...

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