Home-Built Scanning Tunneling Microscope (2015)
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Re: Home-Built Scanning Tunneling Microscope (2015)
#2CA3140 OpAmps also work well.
The comments about 1pF feedback do speak to one of the challenges with feedback stability, where stray capacitance on the proto-board may or may not be present.
Re: Home-Built Scanning Tunneling Microscope (2015)
#3His day-job is pretty mind-blowing, too. He basically works on combing DNA, by squashing it "into nanogrooves [that] are less than 50 nm"
edit: added description of his work
Re: Home-Built Scanning Tunneling Microscope (2015)
#4Can you image non-conductive surfaces with this technique?
Re: Home-Built Scanning Tunneling Microscope (2015)
#5Can you image non-conductive surfaces with this technique?
Nope, the technique for that is an Atomic Force Microscopy[1].
Re: Home-Built Scanning Tunneling Microscope (2015)
#6Ben Krasnow built his electron scanning microscope back in 2011. I never expected to see that one upped.
https://benkrasnow.blogspot.com/2011/03/diy-scanning-electro...
Re: Home-Built Scanning Tunneling Microscope (2015)
#7Can you image non-conductive surfaces with this technique?
Nope, the technique for that is an Atomic Force Microscopy[1]. 1: https://en.wikipedia.org/wiki/Atomic_force_microscopy
And it turns out DIY atomic force microscopes are possible too! (e.g., [1]) It's probably less likely to get all the way to atomic resolution (0.01nm) like a scanning tunneling microscope, but atomic force microscopes can take many types of 1-to-1000nm-scale measurements and are often more practically useful.
[1] https://hackaday.com/2014/04/29/a-diy-atomic-force-microscop...
Re: Home-Built Scanning Tunneling Microscope (2015)
#8CA3140 OpAmps also work well. The comments about 1pF feedback do speak to one of the challenges with feedback stability, where stray capacitance on the proto-board may or may not be present.
Indeed, a 100-Meg feedback resistor is mostly a capacitor. You could think of it as an integrator with DC bias control. This is probably the best article I've seen about transimpedance amplifiers:
https://electrooptical.net/static/oldsite/www/frontends/fron...
Re: Home-Built Scanning Tunneling Microscope (2015)
#9Can you image non-conductive surfaces with this technique?
Best you can do is gold plate the object you would like to scan. Sputter coating is the preferred method.
https://en.wikipedia.org/wiki/Scanning_electron_microscope#S...
Re: Home-Built Scanning Tunneling Microscope (2015)
#10Similar project: http://e-basteln.de/other/stm/overview/