Scanning Probe Microscopy PDF

 1. Introduction (Completed) 1. Introduction...

 1. Introduction (Completed) 1. Introduction In the last two topics in this section of the course we will be focusing on a di7erent subset of techniques which use a scanning probe. Until now, we have looked at techniques than >ring something at the surface (light or high-energy electrons, for example) and measuring the subsequent response by the sample to it. However, scanning probe techniques image slightly di7erently as they measure the changing properties of a probe as it is scanned across a surface, in order to deduce the nature of the interaction between the probe and the sample. This particular topic will look at using this principle to capture images, while the following one will see how we can use the same instrumentation to create patterns on a surface. Scanning Probe Microscopy (Completed) Scanning Probe Microscopy There are over 30 so-called scanning probe microscopy (SPM) techniques, all of which have a similar basic principle of operation. Namely, a physical probe (e.g. a sharp tip) is scanned across a sample's surface and a speci>c interaction with this probe is measured to provide a pixel value. In other words, it is the probe-surface interaction which allows us to produce an image line by line (as in confocal or STED microscopy). At this point you might be wondering, what interaction is being measured? This will depend on the exact scanning probe technique being employed. In this topic we will be looking at two scenarios: We might be measuring an electric current Qowing between our probe and the surface, which is how a scanning tunneling microscope (STM) works. Alternatively, we might have a very sharp tip on a cantilever that can bend in a predictable way. By moving this sharp tip along the surface, forces between the sample and tip will cause the cantilever to derst. 1981 — Binnig and Rohrer invent the scanning tunneling microscope (STM) while at IBM 1982 — Binnig and Rohrer are the >rst people to “see” atoms using STM 1982 — Patent >led by Dieter Pohl for the near->eld scanning optical microscope (NSOM/SNOM) capable of super-resolution 1985 — Binnig, Gerber, and Quate invent the atomic force microscope (AFM) There is incomplete content above. You must complete this before you can proceed through the course. 1986 Nobel Prize in Physics (Completed) 1986 Nobel Prize in Physics Only 5 years after the invention of the STM, Gerd Binnig and Heinrich Rohrer were awarded the Nobel Prize in Physics "for their design of the scanning tunneling microscope”. If you remember, in 1986 the prize was jointly awarded with the inventor of the electron microscope, Ernst Ruska. They were also instrumental in the invention of the AFM, which is arguably one of the most versatile microscopy techniques currently available for studying samples at the nanoscale. Shown here are Binnig and Rohrer with an STM back in 1982. It's considerably smaller than many of the other microscopes we've come across so far! There is incomplete content above. You must complete this before you can proceed through the course.   2. Scanning Tunneling Microscopy (STM) (Completed) 2. Scanning Tunneling Microscopy (STM) Let's take a look at the