Scanning tunneling microscopy sample preparation

Rohrer G 1993 The preparation of tip and sample surfaces for STM experiments Scanning Tunnelling Microscopy and Spectroscopy ed D A Bonnell (Weinheim VCH) ch 6... 

Fig. 19 AFM images of G-wires freshly adsorbed onto mica imaged via tapping mode (a). Same sample imaged by the same tip 24 h later after drying in an oven at 37 °C (b). Low current scanning tunneling microscopy image of G-wires freshly adsorbed on mica (c). Note the preferential orientation is not a sample preparation artefact, e.g., due to rinsing [126]. Reprinted with permission...

The oldest microscopy technique for materials analysis was optical microscopy. Even to this day, for feature sizes above 1 pm, this is one of the most popular tools. For smaller features, electron microscopy techniques such as scanning electron microscopy (SEM) and transmission electron microscopy (TEM) are the tools of choice. A third family of microscopy includes scanning probe tools such as scanning tunneling microscopy (STM) and atomic force microscopy (AFM). In these relatively recent techniques, sample preparation concerns are of minor importance compared to other problems, such as vibration isolation and processing of atomically sharp probes. Therefore, the latter techniques are not discussed here. This chapter is aimed at introducing the user to general specimen preparation steps involved in optical and electron microscopy [3 7], which to date are the most common... 

The high lateral resolution down to the atomic scale is the special merit of scanning tunneling microscopy and spectroscopy. Spatially resolved measurements at T — 10 K with a W tip coated with approximately 10 ML Fe were performed on a sample prepared by depositing 10 ML of Gd on the W(llO) substrate held at 530 K. This preparation procedure leads to partially coalesced Gd islands with a Gd wetting layer on the W(llO) substrate. 

Ultrafiltration. Microscopy Applications Environmental Light Microscopy Electron Microscopy Specimen Preparation for Electron Microscopy Scanning Electron Microscopy Atomic Force and Scanning Tunneling Microscopy. Particle Size Analysis. Sampling Theory. 

If films with smaller grain sizes are to be examined, there are a couple of common alternative techniques for analysis. TEM can measure there are fine details of the surface morphology, but extensive sample preparation is required. Alternatively, scanning tunneling microscopy (STM) or atomic force microscopy (AFM) maybe used, depending on the particular details of the structure and properties of the surface to be examined. Depending on the technique used, the surface can often be examined directly with these techniques, without the deposition of a conductive overcoat. 

---