This page discusses the FTIR system.

Last Updated by: AFB 20160920

Introduction

Fourier Transform Infrared Spectroscopy (FTIR) is a measurement technique that quickly analyzes the optical transmission and reflection properties of a sample.

LASE FTIR System

Bruker Vertex 80v FTIR with a Bruker Hyperion Microscope

Manuals

Hard copies of the manuals are located in the FTIR lab. We are still trying to procure digital copies.

Software

Bruker provides free OPUS software for off-site data viewing and analysis. A download to that software is here:

OPUS viewing software download

The software will download as a .zip folder. Extract the contents of the .zip to a directory of choice on your computer. Then run OPUS.exe (if will show up as the OPUS icon in the folder).

To use the viewing software, the output data/spectra must be saved in an appropriate file format. Once a .o file is loaded into OPUS, use save as, then select the Mode tab to pick the file format. The following file formats should work for both using the viewing software and for any data manipulation you might need to do:

• Data point table (.dpt)

• JCAMP DX

• Galactic

The .dpt is the recommended option, because that is what everyone else in our group uses.

NOTE: OPUS files, i.e. .o files, cannot be viewed with the viewing software

Training

Get trained on the FTIR by one of the senior students. Be sure to read through the procedure below before starting a training session

Procedures

Set-up

1. Add LN2 to the top of the microscope

   1. Try not to overflow the LN2, because it wears down the enamel

   2. Fill until the LN2 holding tank is full

2. Turn on nitrogen purge line using valve by the back of the microscope

3. Start Opus software

   1. Password: OPUS

   2. The microscope is at cryo temperatures and ready for use when the green light (bottom right corner of the screen) is on. It is too warm and not ready for use if the light is red

4. Turn on the microscope (black switch along the back of the microscope, along the bottom and toward the backroom door)

5. IF NEEDED: Change the beamsplitter for the range of measurement desired

   1. Vent optics (~ 2min)

      1. Go to Measure/advanced measure/Basic and select "Evacuate Optics"

      2. ^ same for purging optics

   2. Add correct beam splitter

      1. Update trolley sheet Reinsert the beamsplitter, using red tab to secure the beamsplitter

      2. vent system (~2 min)

Advanced Data Collection Transmission Measurements

Microscope Wizard Reflection Measurements

The general procedure for the reflection measurements is on P.27 of the Hyperion user manual

1. Complete the Set-up above

2. In Opus, select "Start Video Wizard"

   1. select Hyperion 2000

   2. "start"

3. Move the condenser out of the way, i.e. all the way down so any x-y stage movement does not catch the top of the condenser and strain the stage motors

4. OPTIONAL: Reset the xyz stage

   1. Only need to do this if the stage was altered significantly

5. Manually change the objective

   1. On the microscope, move to the 36 X IR (large black objective w/ gold band that says "(36X) NA=0.5")

   2. In Opus, update the objective option in the GUI to 36 X IR

6. Add sample to the stage

7. Find and focus on the sample with the microscope by using the joystick

   1. Set to visible mode. Note that the 36 x IR objective will still work for visible light

   2. Find the particular sample features that you want to measure

   3. Recommendation: focus on the edge of the sample or some feature edge, then move laterally (x-y) to the desired position on the sample

8. Capture image in a region of the sample where the measurement will take place.

9. Take background measurement

   1. Move sample out of the way with joystick and put gold mirror from blue box in the way to collect a background signal for reflection

      1. In visible mode, adjust the focus height to get a focused position on the mirror. Again, focus on the edge first before moving somewhere nice-ish on the mirror surface (there are many crack/scratch marks)

      2. Change to IR (squiggly waveform)

      3. Check that the polarizer is in the IR mode (i.e. almost entirely pushed in)

         1. There is a sliding knob on the left side of the microscope

      4. In Opus Measure/Check signal

         1. Change to ADC mode

         2. Adjust the height using the joystick (twisting for z control) to maximize the signal counts

   2. Things to keep in mind:

      1. Make sure the IR polarizer, 36xIR, and IR light source settings are being used!

      2. Get to a rough max intensity for the IR counts by manually adjusting the joystick, then use "Auto Align" followed by "Fine Auto Align"

      3. Typical gold mirror peak ADC count value is ~4450

   3. Measure the background once, i.e. only collect one background measurement point

10. Take sample reflection measurement

    1. Move back to the sample position using "move xy stage" and click in the far right window

       1. Note: this only moves in x and y. You will still have to adjust z height, which is described below

    2. Change to visible

       1. Readjust the height/focus back to the sample

          1. z height difference between a glass slide and the gold reflecting mirror is ~2500 um

          2. z height difference between a Si wafer (350 um thick) and the gold reflecting mirror is ~2700 um

    3. Change to IR, IR polarizer, and 36 x IR

       1. In Opus Measure/Check signal

          1. Change to ADC mode

          2. Adjust the height using the joystick (twisting for z control) to maximize the signal counts

          3. After rough adjustment with joystick, use "Auto Align" followed by "Fine Auto Align"

          4. Some typical ADC max count values:

             1. Bare Si (350 um thick) = 1450

    4. Set measurement position(s)

       1. Pick a set of data points for where on the sample to collect data. There are several option in Opus, e.g. grid.

       2. Recommendation for homogeneous sample: use 5 arbitrary/random points on top of each other. In theory the output data should be 5 ~identical columns

    5. Set data file path information

       1. Sample name

       2. File name (use the sample name)

       3. Set directory path (desktop/user data/<your file>)

    6. Run scan (~2-3 min)

    7. Do not repeat the scan (unless you need to). Select "End"

11. Viewing and saving the data of interest

    1. Select the data block of interest, for reflection it is the RFTL block

    2. Save as data point table (.dpt) format, which acts as a .csv file

Microscope Wizard Transmission Measurements

The general procedure for the transmission measurements is on P.30 of the Hyperion user manual

1. Complete the Set-up above

2. In Opus, select "Start Video Wizard"

   1. select Hyperion 2000

   2. "start"

3. Move the condenser out of the way, i.e. all the way down so any x-y stage movement does not catch the top of the condenser and strain the stage motors

4. OPTIONAL: Reset the xyz stage

   1. Only need to do this if the stage was altered significantly

5. Manually change the objective

   1. On the microscope, move to the 15 x IR objective

   2. In Opus, update the objective option in the GUI to 15 x IR

6. Add sample to the stage

7. Find and focus on the sample with the microscope by using the joystick

   1. Perform in reflection mode

   2. Set to visible mode. Note that the 15 x IR objective will still work for visible light

   3. Find the particular sample features that you want to measure

   4. Recommendation: focus on the edge of the sample or some feature edge, then move laterally (x-y) to the desired position on the sample

8. Capture image in a region of the sample where the measurement will take place.

9. Take background measurement

   1. Change to transmission mode

   2. Select "Measure background once" and "User defined position"

   3. Change to visible and transmission mode

   4. Move the sample out of the way such that all the light from below clears the edge of the sample and the edge of the stage hole

   5. Optional: adjust the condenser with the coarse alignment knobs until you see a washed out bright white light

      1. In visible

      2. Adjusting the condenser silver knobs until the until the video is washed out with bright light

      3. Close the pin hole via the black knob behind,below,back-left of the stage

      4. Adjust the silver knobs to bring the light into focus so it looks like a circle

      5. Adjust the the silver set screws at the base of the condenser to position the center beam/circle in the crosshairs of OPUS

      6. Open the pin hole

      7. Switch back to IR

      8. ADC counts should be ~18000

   6. Wait 2-5 minutes to allow the nitrogen to purge the atmosphere in the measurement box

   7. Collect background

10. Align sample

    1. Move x-y stage, click in the far right window to actually move the stage to the sample position

    2. Set the measurement points (grid, random points, etc.)

    3. Change to IR mode and go to Measure/Check Signal

       1. Adjust the condenser height to maximize the counts

       2. Adjust the stage via joystick to maximize the counts

       3. Again adjust the condenser height to maximize the counts

11. Collect sample transmission data

    1. Set data file path information

       1. Sample name

       2. File name (use the sample name)

       3. Set directory path (desktop/user data/<your file>)

    2. Run scan (~2-3 min)

    3. Do not repeat the scan (unless you need to). Select "End"

12. Viewing and saving the data of interest

    1. Select the data block of interest

    2. Save as data point table (.dpt) format, which acts as a .csv file

Turn off system

After finishing a measurements:

1. Close the Opus software

2. Turn off the nitrogen feed valve

3. Turn off microscope using switch on the back of the microscope

Troubleshooting

• The Opus software frequently crashes. Restart the software when this happens. Note: the entire measurement must be restarted, including the background

• If you need to power cycle the spectrometer

  • Wait until all the lights are green on the back/top/left side

  • After restarting Opus, you must purge the optics in Measure/Basic Purge Optics