Atomic force microscopes (AFMs) are instruments that allow three-dimensional imaging of surfaces with nanometer resolution. Also used to determine chemical and mechanical properties of surfaces, they and their cousins, collectively called scanning probe microscopes, are the principal enabling technologies in the fields of nanoscience and engineering. Nanoscience and engineering encompass many different disciplines, e.g. physics, chemistry, materials science, electrical engineering, and biology. Their common thread is the mutual focus on understanding, designing, and controlling processes and devices at the nanoscale.

If you complete this course, you will understand the functional principles of AFMs, be able to run one, and interpret the data that you collect. The course has two main parts. The first half of the semester emphasizes instrumentation, the second half interpretation. A bachelor's degree in science or engineering is sufficient background. Previous students have indicated that the course was not only helpful to their research, but also in finding employment. You must pass the course in order to use my AFMs in your future research. Auditors are welcome to sit in the lectures. However, they may not partake in the labs due to the high cost of supplies, the limited number of TAs, and licensing issues.

Course objectives

• To become competent in the use of AFMs and in the interpretation of AFM data
• To develop the ability to write a good lab report
• To gain an understanding of scientific research
• To learn how physics applies to AFMs

Grading

Syllabus

PART I – INSTRUMENTATION

Unit 1, Fundamentals of imaging

Class 1:  Introduction
Class 2:  SPM and AFM instrumentation
IL1:   Laboratory procedures
CL1:  Image processing
IL2:  Acquiring an image

Unit 2, Difficulties of imaging

Class 3:  Feedback and artifacts
Class 4:  Perturbations and noise
Class 5:  Fast fourier transforms
IL3:  Optimizing an image and lateral force microscopy
CL2:  Feedback and noise
CL3:  Fast fourier transforms

Unit 3, Other SPMs and operational modes

Class 6:  Scanning tunneling microscopy
Class 7:  Lateral force microscopy
Class 8:  Operational modes
IL3:  Optimizing an image and lateral force microscopy

Unit 4, Calibration

Class 9:  Probe calibration
Class 10:  Scanner calibration
IL4:  Probe and scanner calibration

Class 13:  Exam 1 on instrumentation

Unit 5, Force-curve mechanics

Class 11:  Potentials, forces, and stiffnesses
Class 12:  Force curves
IL5:   Acquiring and processing force curves
CL4:   Potentials, forces, and stiffnesses
CL5:  Compliance

Unit 6, Tip-sample interactions

Class 14:  Surface forces
Class 15:  Basic mechanical properties
Class 16:  Contact mechanics
Class 19:  Energy dissipation and molecular dynamics
IL6:  Contact mechanics
CL6:  Contact mechanics
CL7:  Molecular dynamics

Unit 7, A glimpse at current research

Class 17:  Student presentations on current research
Class 18:  Student presentations on current research

Class 20:  Review
Class 21:  Exam 2 on interpretation

Calendar

Here is the fourteen-week graduate calendar. We will cover the same material as the undergraduates in sixteen classroom hours, seven computer labs, and six instrument labs. The yellow-shaded topics are those for presentation by students. The blue-shaded boxes indicate the days that we do the activities as one group.

Learning objectives

Unit 1, Fundamentals of imaging

1a.  Describe the differences among SPM, SXM, STM, AFM, SFM, LFM, and FFM.  (PG Sects.1.0, 1.1) 
1b.  Know in which environments an SPM can operate. (PG Sect.1.7) 
1c.  Sketch diagrams showing the difference between constant-height and constant-strength modes. (PG Sects.1.0, 1.1)
1d.  State the advantages and disadvantages of AFM and the ways in which AFM can be used. (IntroAFM)
1e.  Distinguish between the "top-down" and "bottom-up" approaches to nanotechnology. (IntroNST)
1f.  Know the effects of the basic image-processing options. (SPMLab, CL1)
1g.  Describe how to acquire and process a contact-mode constant-normal-force AFM image. (PG Chap.5, UGI Chaps. 1-3, IL1, IL2)

Unit 2, Difficulties of imaging

2a. Describe how a feedback circuit works and how you can control it. (UGI Chap.4, FB, CL2)
2b. Know how to optimize an image. (UGI Chap.4, IL3)
2c. Know how to test for artifacts. (PG Chap.4, UGI Chap.4) 
2d. Identify common artifacts and be able to rectify them. (PG Chap.4, UGI Chap.4)
2e. Identify the four most important types of noise and specify their characteristics. (DraftSect2.2, CL2 )
2f. Know how SPMs are built, situated, and protected so as to limit perturbations. (DraftSect.2.2)
2g. Explain the principles of fourier theory and fourier threshold filtering. (DraftSect2.2, CL3)
2h. Be able to improve SPM images using fourier threshold filtering. (CL3)

Unit 3, Other SPMs and operational modes

Unit 4, Calibration

Unit 5, Force-curve mechanics

5a.  Calculate all the relationships among potentials, forces, and concavity. (DraftSect5.1, CL4)
5b. Understand the origins of cantilever instabilities. (DraftSect5.1, CL5)
5c. Understand why and how raw force-curve data is converted into processed data. (DraftSect5.2)
5d. List the advantages and disadvantages of weak and stiff cantilevers. (DraftSect5.1,5.2)

Unit 6, Tip-sample interactions

Unit 7, A glimpse at current research

7a. Give some examples of current research topics. (student presentations)
7b. Know how SPMs have contributed to this research. (student presentations)

Study materials

Lecture, presentation, abstract, and reading

Communication, etc.

Important times, places, and dates 

The course is held Mondays 9-12:00 in Olin Hall. We start with an hour lecture in OH214, then often split into two groups. One group does a computer lab in OH117, the other an instrument lab in OH009. We meet Mondays starting January 26.