Atomic Force Microscopy Education

Abstract

Atomic force microscopy (AFM) is a crucial part of nanoscience. Despite the simplicity of its design—a cantilever with a sharp tip—learning and teaching AFM can be difficult. For this study, five levels of AFM education were identified from existing educational literature. Information was gathered from a survey as well as interviews given to established AFM educators. Advice, general practices, and a list of resources were compiled into a website and this chapter. These are intended to become a resource to help educators design their own AFM educational experiences.

Appendices

Appendix A: Survey Questions and Responses

This appendix contains survey questions with accompanying responses from those who answered our survey. The responses to question one have been omitted, and the responses to question two reformatted in respect of the privacy of the survey respondents. For every other question, respondents’ answers are organized by the order in which they completed the survey.

Question 2. Organization/Affiliation?

Table 5.3 Organizations/Affiliations reported in the survey

Question 3. Years of experience in AFM education. This question was answered by 22 of the 23 participants. The maximum was 27 years, while the minimum was 0 years. The arithmetic mean of the number of years involved in AFM education was 15, with a standard deviation of 7.

Question 4. What hurdles did you have to overcome in teaching Atomic Force Microscopy (e.g. cost of AFMs or consumables)? Do any remain?

Respondent 1: “Biggest problem is finding time on the equipment as it is used heavily in research.”

Respondent 2: “There is no problem if there is a lab with the AFM equipment and experience.”

Respondent 3: “The cost is not great, in terms of cantilevers, etc. Mostly, though, AFM is just more delicate than SEM, or optical microscopy. So students have a tendency to break things. You have to watch them like a hawk.”

Respondent 4: “(1) Lack of research grade AFM for teaching. Cheap alternatives are not as good. Learning by using them would be rather misleading. (2) Multidisciplinary interest to this technology brings students with different backgrounds. As a result, I typically need a special course to teach about intermolecular forces before effective teaching of scanning probe microscopy.”

Respondent 5: “The initial cost of the purchase of an AFM and later the consumables such as tips, tweezers, etc. In addition, the course or lab needs good teaching assistants who are experiences in using an AFM and preparing samples.”

Respondent 6: “Cost of consumables, complicated equipment to teach (computer software, electronics hardware, optics, physics of oscillating systems). Students have a big hill to climb before they are competent.”

Respondent 7: “AFM to get images is easy but quantitative Images with correct interpretation can be challenging. It was difficult to get access to instruments to large classes.”

Respondent 8: “The only hurdle for me was that there are no “standard” experiments in microscopy. We were lucky to have a good instrument partly through university teaching funds that was designated for use in our Senior Lab course.”

Respondent 9: “The general operation and use of AFM is not too difficult to teach. Obtaining topographical images of a substrate in air is relatively easy to do. This becomes more complicated depending on the information you wish to obtain from the AFM measurement. For instance, obtaining high resolution images (e.g., lattice imaging) is very difficult. It can be challenging to use techniques such as phase imaging. Using AFM for more advanced operations, such as in situ imaging to capture dynamic events in real time, takes time to learn. One of the most difficult aspects of teaching AFM is that much of it is a “black art.” Over time you learn how to obtain better images, but it becomes more of an intuitive feel rather than an exact science. In terms of AFM costs, tips are expensive and it is important that people operating the instrument know to be careful with them. At the same time, you aren’t a true AFM operator unless you've broken your fair share of tips! Advancements in technology are making many of the more complicated aspects of AFM easier. For instance, positioning the laser on the cantilever, engaging the surface, and tuning are becoming more automated, which makes it easier for the user to learn the technique. I don’t foresee these advancements coming to a point that completely eliminates the “art” of AFM; however, this is what makes it fun!”

Respondent 10: “I have been doing AFM for a very long time and when we first started even the people who had invented the technique knew relatively little about how it worked. So, one of the biggest hurdles was figuring out the surface and interfacial processes and determining what was artifact and what was ‘real’ in an image. One of the biggest ‘hurdles’ has always been teaching people how to identify different artifacts and I still get lots of papers to review with incorrectly interpreted data. There were no textbooks on AFM and most people in my field didn't know much surface or interfacial chemistry/physics. I wrote a textbook on Environmental Surfaces and Interfaces that I have used to teach a course and that helps. It has a section on different methods including AFM. I think it's important for students to actually see an AFM in action which can be difficult for a big class. In that case, I break the class up into several smaller groups so that some can visit the AFM lab while others visit XPS, etc. and we rotate.”

Respondent 11: “While we use AFM in our research we do not teach an AFM course or lab.”

Respondent 12: “AFM enters into my teaching principally through a joint undergraduate/graduate course I give on Surface Science. It is mostly a classroom course but sometimes we include an AFM lab module. This module utilizing an existing AFM in another professor’s lab so we have no issues regarding cost. Since it is not the principal focus of the class we do not encounter any issues to overcome.”

Respondent 13: “consumables”

Respondent 14: “Cost was an issue but alleviated by using the AFM in my lab. The biggest hurdle was making sure I had TA support—usually one of the students in my lab. Consumables were covered by a course fee.”

Respondent 15: “Cost for sure. I typically simply describe it in class and show images. ps—[a colleague] forwarded me this survey since I teach it far more than he does.”

Respondent 16: “Equipment cost and availability is definitely an issue. Other issues are: (i) the required background in dynamics takes some time to acquire; (ii) the field is multidisciplinary, so students aren’t generally prepared for it (e.g., engineers like equations but not physics, physicists like the physics, but not necessarily the dynamics and equations, etc.); (iii) until recently there wasn't a good textbook for it, and even now, the available materials are a bit advanced and geared mostly toward graduate students; and finally, (iv) there aren’t too many AFM experts who are familiar with most AFM variants and are available to teach the subject in depth—funding for AFM research is very limited since it is often seen as ‘only instrumentation’ so most researchers may not have the time/resources to dedicate themselves to teaching AFM.”

Respondent 17: “Cost of consumables is an issue. It creates some difficulties for us that our research instrument is also used for teaching.”

Respondent 18: “Cost of AFM was main hurdle. AFM is like many musical instruments. You can get moderately good pretty quickly. To get the best images requires quite a bit of practice and patience. This is something that undergrads don’t always have.”

Respondent 19: “Cost is always an issue. Other issues are instrument maintenance and making sure the instrument does not get damaged. But the biggest issues is to create meaningful, but doable labs for AFM, which is not always an instrument that provides immediate results.”

Respondent 20: “The two primary hurdles are (1) cost of instrument/consumables and (2) long time for learning how to operate the instrument and interpret the data.”

Respondent 21: “I have only taught (a) a graduate course with no lab, hence no consumables and (b) my own graduate students.”

Respondent 22: “Availability of good text books is still a problem. Eaton/West has been a step forward, but I feel like there is still a huge need for more and better books (and other materials).”

Respondent 23: “Cost of a dedicated AFM- access to existing AFM’s (hard to enable inexperienced students to use expensive AFM’s used for research—risk of damage, use of time)—the difficulty in exposing teams of students to AFM when only one person at a time can really use it (with others watching)—time involved in training and writing documentation to prep students.”

Question 5. Did you have any hesitations about creating an AFM lab or course? If so, what were they? Are they now assuaged?

Respondent 1: “I have not taught a specific course on it, but in previous years I used it as part of a general biomaterials/surface science lab course. I had no hesitations at that time.”

Respondent 2: “No.”

Respondent 3: “I still haven’t created a course specifically dedicated to AFM. Rather, I have units on AFM as parts of other courses, like our SEM course, or one of our senior physics labs. That’s the paper you saw.”

Respondent 4: “None”

Respondent 5: “No. In the mid-1990s I saw the increasing applications of AFM in diverse fields as well as the preparation of students for future careers or graduate studies, the training of the use of AFM will be helpful. Besides the concept of nanoscale is easier to believe by seeing an AFM image. Now the AFM are used in many fields and it may be easier to sell the need of AFM education.”

Respondent 6: “The difficulty of getting students trained and the risk of them breaking equipment. It’s still a struggle to train students, but i think it’s worth it. The risk to damage to the equipment is still there. This year, for example, I was forced to come up with $3500 to repair a broken part on the AFM.”

Respondent 7: “No.”

Respondent 8: “No.”

Respondent 9: “I did not have any hesitation. Our lab is open to outside users, so there is always the risk of people using your instrument who have not been properly trained. My students and I take precautions to make sure that outside users and new users in our group are properly trained. Since we almost exclusively work with liquid cells, the most stressful part of AFM is the potential for leaks, which can be costly. We are in the process of expanding our lab. We currently have three AFMs and I have no hesitation to establish a user facility where other groups have access to these instruments. In terms of an AFM course, I have not considered this and do not think there would be enough interest at my institution for a formalized course, although many groups do use AFM.”

Respondent 10: “Again, when I first started doing AFM and running the AFM lab at Stanford, we were using the very first AFM ever sold (by what was then Digital Instruments) and there wasn’t even a manual for it. But, I just dove in and started teaching other people individually or in groups. The biggest problem has always been making sure that people know how to use the instrument correctly and that they identify artifacts. So, if someone is going to use AFM for an actual project s/he needs to spend a lot of time getting to know the instrument or else work with someone who knows it well. Else, data may be produced but they may be incorrectly interpreted.”

Respondent 11: “N/A”

Respondent 12: “We have a course (offered by another professor) on various microscopy tools used for materials characterization that involves AFM. Since another professor offers it I have not had any motivation to offer my own.”

Respondent 13: “Students breaking the AFM, no”

Respondent 14: “None at all. I was able to bring an offering that did not exist on campus despite having several groups using SPM techniques.”

Respondent 15: “We don’t have any AFM labs. It's too costly and there is too much chance for something to break and affect research.”

Respondent 16: “I haven't actually created an AFM course. I have given many introductory lectures on the topic, I have included AFM in my courses as an example, and I have taught small groups of students how to use the instrument, but I have never created nor taught a complete course on it. I have mostly carried out research on the subject with graduate students (mostly PhD students, since the required background takes so long to acquire).”

Respondent 17: “No”

Respondent 18: “Don’t have an AFM lab course. Use it in undergrad research”

Respondent 19: “Creating innovative labs for AFM requires that one tries things out first and creates good documentation—that takes time.”

Respondent 20: “No. “

Respondent 21: “The reason I have never taught a lab class to other students is that the instrumentation is very expensive so (a) I don’t have multiple sets and (b) it has been heavily used for research.”

Respondent 22: “No.”

Respondent 23: “No”

Question 6. What is your advice to prospective AFM educators?

Respondent 1: “You have to allow the students hands on experience.”

Respondent 2: “Keep tracking with the methodology progress. In addition to topographic imaging, there are other AFM modalities, force spectroscopy in the first place. Time lapse imaging is the major attractive feature for AFM making it superior to all other nanoimaging techniques. Note the high-speed AFM that is coming out. It has a lot of potentials with biomedical applications.”

Respondent 3: “Be very patient.”

Respondent 4: “I honestly don't know. Probably, to learn the AFM technique before teaching it :-)”

Respondent 5: “Find time and write proposal applications to funding agencies or talk to school administrators and justify the need of AFM for education.”

Respondent 6: “Structure your program as an apprenticeship if possible with senior students training the new students, with the instructor as the overseer and quality control on all levels.”

Respondent 7: “Let students find out themselves how it works. Most motivating experience.”

Respondent 8: “I think the educational settings involving AFM are so varied that it is hard to give useful advice to another teacher.”

Respondent 9: “Be patient! This technique, like many others, requires time to properly learn. In order to get that “intuitive” feel for the instrument, you need to gain experience. You also must be persistent. Oftentimes you are required to troubleshoot problems, which can be extremely frustrating. If you stick with it, and when necessary consult with the AFM company, you will solve the problems. It is also important to realize that even after you have become an expert, not all AFM runs work. You are always going to have a day that is lost because something went wrong (either with the tip or the sample). This again requires patience.”

Respondent 10: “It takes time. Just because you can produce an image or get a curve doesn’t mean it’s ‘real’ or easily interpreted. Realize that some students will have difficulties with all the tiny parts and with being patient enough to get good images. Modern instruments often are more automated than the older ones but they still require delicate work such as adding a new tip. If you are just going to teach about AFM, make sure you include the pros and cons. If you are going to teach ow to use AFM, take your time so that students can feel comfortable and make sure you teach about artifacts and potential difficulties. Make sure you teach about surface forces and surface reactivity. I guess I could recommend my book but that might be self-serving.;-)”

Respondent 11: “N/A”

Respondent 12: “Include both a significant theoretical and practical component. I think it is important for students to have a good grasp of the scientific background related to any microstructural tool that a student will use in his/her work.”

Respondent 13: “Students will break a lot of probes and even the AFM”

Respondent 14: “Ensure good hands on training and let students guide projects based on their interests.”

Respondent 15: “Find a way to purchase a dedicated teaching AFM that is generally cheaper.”

Respondent 16: “I would have to give this question a bit more thought, since I haven’t yet considered what would be the best way to teach AFM given the constraints. However, careful evaluation of the challenges is always a good start.”

Respondent 17: “It is a good option for upper-division undergraduates.”

Respondent 18: “I would think that a course in AFM is a bit narrow within the milieu of a liberal arts education? Perhaps a one-credit interest/introductory course? Or possibly embedded in a course on microscopy that includes several other technologies.”

Respondent 19: “Take your time to create good documentation and testing things carefully to identify potential pitfalls.”

Respondent 20: “You should not be intimidated about teaching AFM to undergraduate students because the basic instrument setup is fairly simple to teach and students in general show great interest in AFM. We implemented a virtual AFM lab module with two way communications to teach AFM to a large number of undergraduate students and it is working very well. There are also a lot of AFM training materials online.”

Respondent 21: “N/A”

Respondent 22: “None in particular.”

Respondent 23: “Plan ahead, secure access to an instrument, recruit an experienced TA for help with training, take advantage of existing resources e.g. nano hub website, existing books”

Question 7. Do you believe exposure to AFM benefits students? Why?

Respondent 1: “Yes. It is a powerful tool, but very different than traditional surface science tools that are used in vacuum. I don’t believe it occurs to students that this might be available without being introduced to it.”

Respondent 2: “AFM is getting as a rather routine imaging tool and students should be exposed to this technique.”

Respondent 3: “Sure, especially physics majors. A lot of our majors are interested in doing research, so it helps them to learn advanced tools.”

Respondent 4: “Yes, if students decide or think they would work with any aspect of surface science in the future. AFM is one of the fastest-growing microscopy, which is way more than just a microscopy. It is one of the most important (if not the) techniques responsible for the emergence what is called nowadays nanotechnology. Knowing it will definitely benefit any students decided to be familiar with nano tech.”

Respondent 5: “Students who took the AFM course not only can absorb the scale of nano but can also think its applications in various fields. The skill in AFM is useful for their future graduate study or work in diversified areas.”

Respondent 6: “Yes, it's one of the few accessible tools that give students direct access to the nanotechnology revolution. AFM also contains many aspects of fundamentals from their courses, e.g. physics, optics, controls.”

Respondent 7: “Yes. They see that a simple instrument can reach atomic resolution. This is inspiring.”

Respondent 8: “Yes—it provides training in a truly modern experiment, which is rare in Physics.”

Respondent 9: “I feel that AFM is one of many analytical techniques. I personally have benefitted from knowing how to use AFM since my research heavily relies on the technique; however, I would not say it carries any more weight than other techniques in the sense that it good for scientists to have exposure to a variety of instruments. If your research can benefit from AFM, then certainly it is worth learning. If your work only requires occasional use of AFM, then the time invested to become an expert may not be necessary. I think the benefit really depends on the user and how AFM can be used in the research project.”

Respondent 10: “Absolutely. Surfaces and interfaces are extremely important in many fields of science and engineering and AFM is a very approachable instrument that provides great data as long as one has the background needed to correctly interpret the data.”

Respondent 11: “N/A”

Respondent 12: “In materials science and engineering (my department) and related fields AFM is an important characterization tool and all students should have some exposure to it.”

Respondent 13: “yes, it’s a good characterization technique”

Respondent 14: “Yes—SPM techniques are now an essential tool in a wide range of research fields. It is a skill set that is often in demand. I have had more than a few students tell me that the AFM course helped them in interviews for Post-doc experiences and research positions.”

Respondent 15: “Yes. Especially in a Materials Science department. This technique is becoming very widespread in industry.”

Respondent 16: “Most definitely. AFM is one of the most powerful and versatile tools in nanotechnology. I think that we are at a disadvantage here, especially relative to Japan and Europe.”

Respondent 17: “A variety of instrumentation experiences are always helpful.”

Respondent 18: “Yes. It’s a tool to interest them in conducting research. A very powerful tool.”

Respondent 19: “It’s a very common research tool, it’s very versatile and very visual. It can applied in many different contexts (materials, biology etc).”

Respondent 20: “Yes. Students are impressed by what AFM does and the exposure motivates students to learn more about nanotechnology.”

Respondent 21: “N/A”

Respondent 22: “Yes, as it is a very versatile and in many ways unique research tool.”

Respondent 23: “Yes, it gives them the opportunity to use a real research tool; to visualize something not observable either to the naked eye or through a microscope; to appreciate the importances of contact and tribology; to understand the instrumental methods that have been a key component of launching nanotechnology; to understand how scientific research equipment works.”

Question 8. Do you see a future where AFM becomes more prevalent throughout all levels of education? Why or why not?

Respondent 1: “Yes. There will be increasing numbers of used AFMs available, making it possible for all levels of schools to have access, and with the increase in students understanding of nano in the world, an AFM makes more sense.”

Respondent 2: “I would not say prevalent. It should be taught along with all other imaging disciplines, such as confocal microscopy.”

Respondent 3: “I see SEM becoming more prevalent before AFM does. SEM works at TV rates, and even the fastest AFMs aren’t there yet (the ones with scan rates at ~100 Hz, for example, and that only for flat samples). People aren’t as patient as they need to be with AFM. SEM is easier. And the tabletop SEMs are reasonably priced-sort of.”

Respondent 4: “As any technology, AFM has the basic and advanced levels. The basic level would be okay to include in a course on experimental techniques for undergrads. The advanced level is definitely for graduate students. The reason for inclusion I described above.”

Respondent 5: “In the one credit AFM course with lab there were both graduate students and undergraduate students. But in the experimental physics course mostly undergraduate junior students perform the AFM experiment.”

Respondent 6: “There is the opportunity certainly, if the issues of cost and ease of use continue to be improved.”

Respondent 7: “I hope so. Over the last decade instruments have become easier to use, however, we are still far away from a one-button take image instrument. But I see this coming in the near future.”

Respondent 8: “Instrumentation costs are too high for this to become really common. I think it will increase as the cost of commercial instruments decreases though.”

Respondent 9: “With the increased interest in nanotechnology and advanced materials synthesis, I do believe that AFM is becoming, and will continue to become, more prevalent. I am not certain if undergraduate students need to learn this technique, but they should at least be aware of its operation and what can be gained from it. I teach a nanotechnology section as part of a freshman introductory course, and in this section I introduce the students to AFM. I also teach a graduate elective (Colloids and Interface Science) where I spend time discussing the technique. To this end, I do expose a variety of students to AFM.”

Respondent 10: “Yes. I have brought my AFM into elementary and high school labs many times over the years, and started doing this about 25 years ago. Why? Because the instrument tends to be fairly portable and inexpensive. It's also a great instrument for students working on science fair projects.”

Respondent 11: “Not really. It is very nice technique, but is only one of many. It is not cheap and the bar to entry is somewhat high.”

Respondent 12: “I think it is important right now for both undergrads and graduates students to be exposed to AFM as it is an important and standard tool as mentioned above.”

Respondent 13: “maybe, there are high costs involved”

Respondent 14: “Possibly—at undergraduate levels providing hands-on experiences for large classes will become a challenge. Without hands-on experiences, I think the impact will be less.”

Respondent 15: “Only if it becomes cheaper.”

Respondent 16: “I am not sure this will be the case in the US. AFM research is still dominated by Europe and Japan (this has been the case for a long time). We have a relatively small group of AFM researchers in the US. They are very good, but they are relatively few. We have many AFM users, but teaching AFM requires a bit more than that.”

Respondent 17: “No opinion”

Respondent 18: “Probably not. Why should AFM be more important than some of the light microscopy imaging technologies, or TEM, or SEM, etc.”

Respondent 19: “I think it will remain somewhat specialized, because doing really interesting things with it requires skill and previous knowledge. Imaging some prepared sample is nice, but does not really teach very much unless you prepare the sample yourself and know what you are looking for. Force measurements require even more prior knowledge.”

Respondent 20: “Yes because AFM is an essential tool for nanotechnology.”

Respondent 21: “Yes, there are now cheaper AFMs that could be dedicated to teaching and that would solve a lot of the problem.”

Respondent 22: “Not really.”

Respondent 23: “Yes, since lower cost mass-produced systems should eventually become available, allowing students to use, explore, and innovate. This hinges on easy-to-use mass-produced systems, perhaps through MEMS technology.”

Appendix B: Bibliography

This appendix contains a list of sources deemed important for future educators. It contains resources for material as well as textbooks and previous course offerings.

Websites

• http://www.afmworkshop.com/afm-webinars.html

• http://www.afmworkshop.com/atomic-force-microscope-for-educators.html

• http://www.aif.ncsu.edu/hands-on-instrument-operation-and-sample-preparation/

• https://www.bruker.com/service/education-training/training-courses/afm-optical-training-courses.html

• http://www.education.mrsec.wisc.edu/nanoquest/afm/index.html

• Gwyddion Home, Gwyddion, http://gwyddion.net/. Accessed 7 Feb 2016

• http://lnf.umich.edu/nnin-at-michigan/afm/

• http://nanohub.org/courses/afm1

• http://proed.acs.org/course-catalog/courses/understanding-and-utilizing-atomic-force-microscopy-from-basic-modes-to-advanced-applications/

• http://www.teachnano.com/education/newsletter/index.html

• http://www.wpi.edu/academics/physics/AFM/nanoed_resources.html

• https://www.youtube.com/user/AtomicForceMicro/playlists

• https://www.youtube.com/playlist?list=PL3592A61EEF52B29A

Journal Articles

• D. Lehmpuhl, Journal of Chemical Education 80, 5 (2003)

• H. Margel et al, J. Chem. Educ. 81, 4 (2004)

• G. Planinsic and J. Kovac Physics Education 43, 1 (2008)

• N. Burnham, Journal of Nano Education 5, 2 (2013)

• H. A. McNally, IEEE Nanotechnology 7, 19 (2013)

• N. A. Burnham, A. Arcifa, M. Divandari, C. Mathis, S. N. Ramakrishna, and N. D. Spencer, Accepted for the 2015 Conference on Laboratory Instruction Beyond the First Year of College, College Park, Maryland, 22–24 July 2015.

Textbooks

• Pier Carlo Braga, Davide Ricci, Atomic Force Microscopy: Biomedical Methods and Applications, Methods in Molecular Biology, Humana Press 2004

• Peter Eaton, Paul West, Atomic Force Microscopy, OUP Oxford, Mar 25, 2010—Science—256 pages

• Greg Haugstad, Atomic Force Microscopy: Understanding Basic Modes and Advanced Applications, John Wiley & Sons, INC., Publication, 2012