Standard Operating Procedure

Transcription

1 Standard Operating Procedure Nanosurf Atomic Force Microscopy Operation Facility NCCRD Nanotechnology Center for Collaborative Research and Development Department of Chemistry and Engineering Physics The University of Wisconsin-Platteville 208 Ottensman Hall, Platteville Wisconsin, Lab Director James P. Hamilton, PhD Wisconsin Distinguished Professor, Department of Chemistry and Engineering Physics The University of Wisconsin-Platteville Scope This SOP details how to use the basic functions of the Nanosurf AFM. Last Revision:

2 Table of Contents Instrument Overview 3 Changing the Cantilever 5 Check Alignment of Cantilever 8 Running a Scan 12 Topography Data Analysis 21 References 29 2

3 I. Instrument Overview Figure 1a: AFM Instrument Overall Setup Figures 1a and 1b 1. Scan Head Cable 4 2. On/Off Switch 6 3. USB Cables to PC 4. Video Camera Cable (backside) 5. Power Cable 1 6. LED Status Lights 7. easyscan 2 Controller 2 8. AFM Scan Head Assembly 3 9. Scan Head Case 10. AFM tool set Cantilevers, new and used Figure 1b: easyscan 2 Controller with built-in AFM Basic Module 3

4 Figure 1c: AFM Apparatus 1 Scan Head Cable 6 Leveling Screws 11 Sample Slide 2 Video Camera Cable 7 Stage 12 Cantilevers 3 Video Module 8 Button Magnets 13 Tool Case 4 Level 9 Scan Head 14 Cantilever Insertion Tool 5 X & Y Plane Adjusters 10 Air Table 15 Pointed Tweezers Figure 1d: Nanosurf AFM Tools and Replacement Probes 4

5 II. Changing the Cantilever A. The Cantilevers for the AFM will need to be replaced based on usage. Overtime Cantilevers will either wear out or break. This procedure demonstrates how to properly change an AFM Probe Tip 1. Nothing should ever touch the Cantilever, especially the tip end Figure 2a: Cantilever 2. The Cantilever Holder Spring is very delicate and should not be bent B. Removing the Scan Head 1. Be sure the AFM is powered OFF. Remove the Scan Head Cable, Video Camera Cable and Ground Cable from the Scan Head 2. Remove the Scan Head from the AFM Stage and flip the Scan Head upside down, setting the Scan Head onto a flat and clean surface Figure 2b: Properly removing the Scan Head 5

6 3. Place the Cantilever Insertion Tool into the designated hole behind the Alignment Chip, raising the Cantilever Holder Spring to the vertical position 1 2 Figure 2c: Raising the Cantilever Holder 4. The Cantilever can now be replaced. Using the Pointed Tweezers, carefully remove the old Cantilever from the Scan Head Figure 2d: Removing the old Cantilever 5. Discard the old Cantilever into the discarded Cantilever Case. The discarded Cantilever Case is identified by a label Figure 2e: Used Cantilever s Case 6

7 6. Open the case of new AFM Cantilevers. Using the Pointed Tweezers, acquire and install one of the Cantilevers onto the Alignment Chip a) The new Cantilevers are always oriented face-up b) This is very difficult. It s necessary to have the Cantilever placed properly onto the Alignment Chip and be as gentle as possible c) Let the Cantilever fit into the Alignment Chip in the Scan Head d) Verify Cantilever doesn t move with respect to Alignment Chip (1) Cantilevers are very fragile and expensive. Dropping or mishandling a Cantilever will break it. It s wise to practice handling with a used Cantilever and Pointed Tweezers 7. Gently pull the Cantilever Insertion Tool out of the hole. The Cantilever Holder Spring will close and hold the Cantilever tightly in place 8. Once Cantilever is installed, place the Scan Head back onto the Stage a) Slowly place the Scan Head onto the Stage, minding the Cantilever so it doesn t touch anything 9. Install Scan Head Cable, Video Camera Cable and Ground Cable cables into the Scan Head 10. With a Level and Leveling Screws, adjust the Scan Head so it is level 11. Turn the AFM ON Figure 2f: Level Scan Head 12. Check for alignment of the Cantilever 7

8 III. Check Alignment of Cantilever A. To check for alignment of the Cantilever 1. Visually check the Cantilever. A laser beams directly at where the Cantilever should be set. If laser light is very intensely shown on the Stage, the Cantilever needs to be re-centered. 2. Open the Nanosurf Easyscan 2 Icon located on the desktop Figure 3a: Nanosurf Easyscan 2 Icon a) Once opened, the Nanosurf Easyscan 2 screen will appear Figure 3b: Nanosurf Easyscan 2 Main Window 8

9 b) In the Operating Mode Panel, under the Mounted Cantilever Section, select NCLR Figure 3c: Changing the Mounted Cantilever Option c) In the Operating Mode Window, under the Operating Mode Section, select Dynamic Force Figure 3d: Changing the Operating Mode 9

10 d) In the Operating Mode Window, scroll down to the Mode Properties Section and select Set. The Set button is not initially visible in the Operating Mode window. Figure 3e: Setting the Parameters e) The Vibration Frequency Determination Window will appear Figure 3f: Checking Vibration Frequency Determination 10

11 f) In order for a proper alignment of the Cantilever, the Vibration Frequency Distribution coordinates must be within the parabolic curve of the frequency sweep. (1) If the coordinates are not within the parabolic curve of the frequency sweep, the Cantilever will need to be readjusted. (2) If the coordinates are within the parabolic curve of the frequency sweep, the Cantilever was set correctly. Click OK 11

12 IV. Running a Scan A. Open the Nanosurf Easyscan 2 Icon located on the desktop Figure 4a: Nanosurf Easyscan 2 Icon 1. Once opened, the Nanosurf Easyscan 2 screen will appear Figure 4b: Nanosurf Easyscan 2 Main Window 12

13 2. In the Operating Mode Panel, under the Mounted Cantilever Section, select NCLR Figure 4c: Changing the Mounted Cantilever Option 3. In the Operating Mode Window, under the Operating Mode Section, select Dynamic Force Figure 4d: Changing the Operating Mode 13

14 4. In the Operating Mode Window, scroll down to the Mode Properties Section and select Set. The Set button is not initially visible in the Operating Mode window. Figure 4e: Setting the Parameters 5. The Vibration Frequency Determination Window will appear Figure 4f: Checking Vibration Frequency Determination 14

15 6. In order for a proper alignment of the Cantilever, the Vibration Frequency Distribution coordinates must be within the parabolic curve of the frequency sweep. a) If the coordinates are not within the parabolic curve of the frequency sweep, the Cantilever will need to be readjusted. b) If the coordinates are within the parabolic curve of the frequency sweep, the Cantilever was set correctly. Click OK 7. Place the sample onto the Stage a) It is important to not strike the Cantilever with the sample when loading the sample onto the stage b) Use the Leveling Screws to raise or lower the Scan Head to properly insert the sample underneath the Cantilever 8. When the sample is directly under the Cantilever, use the Leveling Screws to lower the Scan Head towards the sample a) Lower the Scan Head as close as possible without touching the Cantilever against the sample b) The sample should be close enough to the Cantilever so that the samples surface is visible on the video window in the Nanosurf Easyscan 2 Positioning window c) Carefully re-level the Scan Head with the Leveling Screws to get a level surface 9. In the Positioning Window, lower the Cantilever towards the samples surface by pressing the Advance button (Figure X) a) The Cantilever should be close enough as to see a reflection of the Cantilever on the sample. b) Do not attempt to contact the surface with the Cantilever or it will break 15

16 Figure 4g: Manually Approaching the Sample 1. Click the Approach button which will have the computer lower the Cantilever towards a scanning distance of the sample surface c) When completed, the Approach Done window will appear Figure 4h: Scanning the Sample 16

17 d) Click OK 10. The Cantilever will now begin to scan the sample in a 8.8µm 2 section a) The X-Y topography of the sample is at the top of the Imaging Window. Below X-Y topography scan is the Z-topography scan. b) To get consistency between samples, it is important to have the X-topography scanning surface as level as possible. To do so: (1) In the Imaging Options Section on the left side of the Topography Scan window, there is the X-slope adjustment. Using the adjustment, increase or decrease the degree of slope based upon the samples slope (2) Wait a moment for the Cantilever to adjust to the new slope before making a secondary adjustment. The X-Y topography scan window will restart, so it s important to adjust the slope early (3) When the ends of the Z-topography are relatively close to the Mean Fit line, the adjustment is complete Figure 4i: Adjusting X-axis while Scanning Sample 17

18 c) Wait for the scan to complete the 8.8µm 2 section (1) If the scan is usable for analysis, at any time during the scan, click the Finish button at the top of the Imaging Window (2) To acquire an image of the scan for analysis, at any time during the scan click the Photo button at the top of the Imaging Window (3) If the Finish or Stop button is not clicked during the initial scan, the computer will continue having the Cantilever scan the same area. It s important to not over-scan once an acceptable picture is acquired as to not wear out the Cantilever Figure 4j: Selecting Scanner to Stop After First Scan 11. When the scan is complete and the Photo button is selected, the image of the full scan will appear 18

19 Figure 4k: Sample Finished Scanning 12. Save the image for analysis by going to: File Save As Figure 4l: Saving Sample Scan 19

20 13. Label the sample appropriately and in a pre-determined directory. 14. Save the image. 15. Close both the Image Window and the Imaging Window which will then bring up the Positioning Window a) Click and hold down the Retract button to raise the Cantilever from the sample surface. b) Once the Cantilever is appropriately far enough away from the sample surface, the sample can be carefully removed from the Stage on the AFM (1) Do Not directly lift up the sample from the Stage surface, but slide it away from the Scan Head before lifting. The Cantilever is far enough to remove the sample, but not that far! 16. If multiple samples are to be scanned, repeat the scanning procedure from step 7. 20

21 V. Topography Data Analysis A. Many different analyses can be done on the topography of the sample that was scanned. The procedure below identifies the desired data acquisition of the sample B. On the desktop, open Gwyddion Figure 5a: Gwyddion Icon 1. The following window will appear Figure 5b: Gwyddion Main Window 2. Click File Open. Select the proper sample, then click Open 21

22 Figure 5c: Gwyddion Open File Window 3. The following screen with the sample should appear Figure 5d: Gwyddion Sample Window 4. The sample topography will need to be adjusted to acquire a proper statistical analysis of the surface. To do so, a) In the Tools Section of the Main Window, click on the Correct Horizontal Scars (strokes) Icon. (1) Repetitive clicking of the icon will remove the horizontal white lines. (2) Notice the image difference between the image below and the image in the previous step. 22

23 Figure 5e: Correcting Horizontal Scars b) In the Data Process Section of the Main Window, click the Remove Polynomial Background icon which will bring up the following screen. Figure 5f: Removing Polynomial Background (1) Click OK (2) Notice the image difference between the image above and the image in the previous step 23

24 c) In the Tools Section of the Main Window, click on the Level X or Y Lines with Polynomials Icon. (1) Click Apply, then exit out of the Polynomial window (2) Notice the image difference between the image below and the image in the previous step Figure 5g: Leveling X or Y Lines with Polynomial 5. To acquire a 3D view of the surface sample area, a) In the View Section of the Main Window, click on the Display a 3D View of Data Icon Figure 5h: 3D Topography Icon Location 24

25 b) The 3D plot window of the sample surface window will appear Figure 5i: 3D Topography Forward Window c) The 3D plot can be rotated in any direction as well as stretched or retracted. It is a excellent visual tool for surface mapping d) Once an adequate 3D image is obtained, save the image by clicking the Save icon in the 3D Topography Forward window 6. To acquire statistical data of the sample topography, a) In the Main Section of the Main Window, click on DataProcess Grains Mark by Threshold Figure 5j: Data Process of Grains by Threshold Location 25

26 b) This will bring up the Mark Grains by Threshold Window Figure 5k: Data Processing of Grains by Threshold c) Select the minimum height the computer should include in the coating of the sample. This can be done by either (1) Threshold by Height scroll bar (nm) (2) Threshold by Percentage selector (%) d) The coloring will display the areas that are that height, in nm, or above the selection made e) Click OK once completed f) In the Main Section of the Main Window, click on DataProcess Grains Statistics g) This will bring up the Grains Statistics Window 26

27 Figure 5l: Grain Statistics Window h) Any statistical information on the sample coating will be in this window. All statistics are based off of the height selection made prior. Adjust the height requirements as necessary. i) Record any information needed from this data analysis 7. To acquire topography data on a specific portion in the sample, a) In the Tools Section of the Main Window, click on Extract Profiles. The profiles window will appear Figure 5m: Extract Profiles Window 27

28 b) On the image, click and drag across the portion desired. On the Profiles window, a z-scale topography profile will appear. This profile can be adjusted based upon the length and area desired Figure 5n: Sample Profiles Window c) Multiple profiles can be made to compare areas of the sample d) Click Apply when finished to acquire the profile graph. It will open in a new window 28

29 VI. References 29