(Nearly) Everything you ever wanted to know about AFM but were afraid to ask…

One of the things I’ve been meaning to pull together for a while are a collection of articles about AFM, the different types of probe tips and coatings and why you might use one kind of probe over and above another.

Inevitably it has become one of those jobs that is always superseded by something else more pressing and urgent for the business.

However, one of the things I am gradually getting used to as we expand and grow as a company is that not everything needs to rest with me anymore. We’re very pleased to have welcomed Máire Power onboard in the last couple of months as our Marketing Coordinator. Máire’s background, with her PhD in physics and her experience as a freelance ESL scientific editor, makes her the ideal person to author our first set of articles and application notes. And brilliantly it takes another job off my ever expanding to do list!

We’ve focused on four main areas and you can link through to the articles below, or alternatively you can access these (and other materials we’ll be producing) anytime through the ‘Resources’ section of our website:

Atomic force microscopy (AFM) for scientists

  • What is AFM?
  • What are the advantages of AFM over SEM as a nanoscale imaging tool?
  • How is AFM used in STEM disciplines?

The superiority of conical tips in atomic force microscopy (AFM)

  • How do tip properties affect AFM imaging?
  • What are the disadvantages of pyramidal/tetrahedral tips?
  • Why is conical superior to the other two shapes?

Reflective coating of the cantilever in atomic force microscopy (AFM)

  • Why is a cantilever coated?
  • What are the disadvantages of coating?
  • What are the main types of coating used?
  • What are the usages of tip types with different coatings?

Vertical Probes in Lateral Molecular Force Microscopy (LMFM)

  • What is the difference between standard horizontally mounted cantilevers and vertically-oriented cantilevers (used for LMFM)?
  • What are the disadvantages of using horizontally mounted cantilevers?
  • What are the advantages of LMFM tip-less imaging?
  • What are the applications and usage of LMFM to date?

Please do take a look at these resources and as ever we’d love to hear your feedback. What do you find particularly useful about these or any other articles, application notes etc. you’ve used? What other resources might you or your students and colleagues find useful in their work?


What AFM probe type do you need most?

As many of you know, I'm really keen that as a company we're working in tandem with the needs of the AFM community. 2018 is all about expanding our product range and we need you!

We'd really appreciate if you could fill out this really quick, 1-question only survey, letting us know what type of AFM probe you'd most like to see us develop next.

We're already able to offer the Scout 350 model of general-purpose AC-mode silicon AFM probes, suitable for non-contact/tapping modes in air, on hard samples and stable softer samples. Additionally, we also have our NuVOC range of ultra-soft probes for use in vertical orientation instruments.

You'll have also seen our new Scout 70 model of AFM probes, a general purpose AC-mode silicon AFM probe, which can now be applied to high resolution imaging of soft samples. In case you missed the product release last month, you can still read about the different versions of the Scout 70 here.

Our production team are packed with ideas on the different types of probes we could develop. You input in our survey will help shape our focus for the next few months. I really appreciate your help with this.


New Year, New Product

The New Year is traditionally a time to make resolutions, set goals for the year ahead and embark on new challenges. It's no different here at NuNano HQ, and we're kicking off things with a new product!

The new probe means that our consistent tip sharpness and minimal variation of mechanical properties can now be applied to high resolution imaging of soft samples.

The Scout 70 is a general purpose silicon AFM probe for imaging in AC modes (non-contact/soft tapping) and force modulation, with a nominal 2 N/m spring constant and 70 kHz resonant frequency, making it ideal for imaging delicate samples or objects that are loosely adhered to their substrate surface.

With two other variants, the Scout 70 is also available as Scout 70 HAR with a high aspect ratio tip for deep trench imaging. The Scout 70 T, with its lower resolution tip, is perfect for step height measurements and getting new AFM users started. All probes are available either uncoated or with reflective aluminium coating on the backside of the cantilever.

Our new probe allows users to access a lower force regime whilst maintaining the same high standards of reliability you've come to expect from our other products.

Applying our proprietary manufacturing process to our Scout 70 probes has meant we've been able to achieve the same tight dimensional control of the cantilever, which in turn ensures there's less variation in the mechanical properties of our probes.

 SEM image of our new Scout 70 probe

SEM image of our new Scout 70 probe


About Scout 70 AFM probe Model

The Scout 70 model of AFM probes have been specifically developed to provide the same exemplary dimensional tolerances and tip sharpness characteristic of all our AFM probes. Click on the links below for more detailed specifications and pricing:

  • Scout 70 - general purpose AC mode silicon AFM probes, suitable for non-contact/soft tapping and force modulation modes in air, on softer samples. Spring constant: 2 N/m. Resonant frequency: 70 kHz.
  • Scout 70 HAR - as above, but featuring a high aspect ratio tip with a cone angle over the last 1 μm of less than 15 degrees.
  • Scout 70 T - a lower resolution version with a tip radius of between 10 - 40 nm, perfect for training new AFM users and for applications where price is more important than tip sharpness.

As with all NuNano products, the Scout 70 model is compatible with most commercially available AFMs. For harder samples, including stable softer samples, our Scout 350 model is also available.

I look forward to announcing further product developments later in 2018, and as always I'm keen to hear about the AFM imaging challenges that you face as that gives me a real drive to help support the AFM community.

For more information, to request a datasheet, free sample, or if you'd like to meet with me to discuss your needs further please call +44 117 299 3093 or email info@nunano.com

Season's Greetings: 3 things you need to know when setting up a scientific company

December is a short (and busy) month for everyone, so we'd simply like to take this opportunity to wish you all a very warm and happy winter break. See you in 2018.

(For those of you still in the office for whatever reason, why not grab a cuppa and have read of my article 'How to build a nanotech company' published in this months Nature Nanotechnology. In it I've shared my three top tips on what you need to know if you're thinking of setting up a scientific company. As always let me know your thoughts and your top tips below!)


5 top tips for effective AFM imaging: a beginners guide

The atomic force microscope is an amazing device. I remember the first time I ever used one, I was completely blown away by what I was able to see.

But I also remember that they can seem pretty quirky things until you get a bit more familiar with them. Using one is a lot like learning to drive - the learning doesn't really begin until you get out on the road on your own. It's then that you discover the nuances of driving, when everything your instructor had to remind you to do becomes second nature.

 Caution, learner driver!

Caution, learner driver!


In real life, hands on experience of working with an AFM can be as daunting as taking your first car out for a spin. Often students and post-docs can find themselves nudged towards the AFM by their supervisor or peers. Wide encouraging smiles and nods of heads suggest that if they just crack on they'll soon get the hang of the thing. And they do.

But here are my five top tips to make the first couple of rides out with your AFM a bit less bumpy for you...

1) Sample prep - it's really important that you are highly disciplined when preparing your sample. You need to make sure that you repeat the same steps each time. If you deviate in your prep, there's a good chance that it will interact differently during imaging, which will affect what you're able to see with the AFM.

2) Know what you're expecting/wanting to see - You need to have a good understanding of the probable dimensions and shape of sample features and structures BEFORE you start. What width and height are my features? Are they evenly distributed across the sample or sporadically clustered? Then set your parameters on the AFM accordingly. Having the settings wrong can result in long hours of futile effort with little reward. 

3) Pick the right probe for the job - the right probe will depend a lot on your sample, and the choice of probes available can be daunting. The first thing to consider is the sample material, then choose a probe that will maximise imaging resolution and stability whilst not damaging the sample. Standard AC mode silicon probes (for tapping/non-contact) will be perfectly fine for imaging a wide range of materials in air, but things get tricky when the sample is softer or when imaging is performed in liquid. Then what about surface topography - are we talking salt flats or alpine peaks? A probe with a high aspect ratio tip might be needed to image the bottom of a trench. The list goes on. If you're not sure what you need then give us a call. We're always willing to offer advice.

Final word regarding probes - always consider whether the probe is brand new or if it's been used before, and don't underestimate the amount of contamination there can be in a laboratory environment. I would always advocate using a new probe if you want those perfect images for a publication.

4) Are you aligned correctly? - You need to make sure that you've aligned the laser spot on the end of the cantilever (as close to the tip as possible). Sounds simple, but for new users, not familiar with the construction of an AFM probe, it's all to easy to get a good laser reflection on the detector but not actually be reflecting off the cantilever. Knowing the size and shape of the different components of the probe (upside down of course) is crucial. Aligning the laser at the end of the cantilever will give you the best sensitivity.

 For best imaging, the laser should be aligned at the very end of the cantilever.

For best imaging, the laser should be aligned at the very end of the cantilever.


5) Practice makes perfect - When you start driving, you can't expect that the first time you get behind the wheel of a car you'll drive perfectly and effortlessly arrive at your destination in good time. Likewise, when you start out working with your AFM don't expect to get perfect images first time. In fact a lot of the scientific insights arises from the problem solving, figuring out why you're not seeing what you think you should see and changing your process accordingly. Keep at it and you will find that you become much more attuned to how the AFM and your sample are interacting. And, when it doesn't work you can quickly identify what the underlying issues might be.

Doubtless this will all make using AFM sound a bit fiddly but when you started driving a car it probably felt like there were a million different things that you had to think about all at the same time. Now you check your mirrors regularly as a matter or course and don't have to consciously remember 'mirror, signal, manoeuvre' etc.

If you're already an experienced user then this is all pretty obvious, but whatever your level of knowledge and skill please feel free to print this out and stick it on the wall (near the AFM...) to help those less familiar with using the instrument.

And as ever we'd like to hear from you - what are your top tips for working with AFM? What was your first experience like? What is the one piece of advice you always make sure to pass onto first time AFM users?

(With thanks for the input from Dr. Rob Harniman, Technician in Atomic Force Microscopy, School of Chemistry, University of Bristol, UK)