Application examples

In the following, explicative examples of industrial applications are shown to emphasize the capabilities of the MAXPEEM beamline.

Au-seeded 100 nm thick InP nanowire (NW) with an undoped segment sandwiched between highly sulfur doped n-type segments (n-i-n-NW), as depicted in the schematic on top of the figure. (A) SE image of a cleaned InP n-i-n-NW (hv=133 eV, KE=0 eV). (B) Intensity profile along the marked line in (A). The dotted vertical lines mark the two space charge regions (SCRs) that are 300 nm (left) and 200 nm (right) wide. M.Hjort et al. Appl. Phys. Lett. 99, 233113 (2011)
Initial oxidation of aged EN 1.4509 ferritic stainless steel studied by SPELEEM. (a) MEM image of the annealed surface, µPES spectra of (b) Nb 3d transition and (c) Si 2p transition before and after 10 L oxygen exposure at 650 °C. The analysis area of µPES spectra is indicated in (a) by dashed line. (d) XPEEM image of the Si 2p (SiO₂) transition after 10 L oxygen exposure at 650 °C, and (e) line profiles showing the intensity variation of the Si 2p signal across different microstructural features. A: Laves-rich grain boundary and an intragranular Laves phase particle; B: TiNeNb(Fe)C precipitate and a Laves-poor grain boundary.                        H.Ali-Löytty et al. Int. J. Hydrogen Energy 37, 19 (2012)

 

Real time experiments

In the following, four real time studies are presented to give a taste of the in situ and live experiments that can be performed at MAXPEEM.

 

Real time intercalation of 3ML Ge below graphene buffer layer on SiC(0001) is shown in the video. The intercalation process is activated at T> 700 °C providing high mobility to Ge atoms. The variation in the contrast along the terraces of the sample indicates the areas where intercalation occurs. The process is stopped as soon as the temperature is decreased to about 670 °C. STV=0.5 eV, FoV=25 μm².

 

Real time LEEM is recorded during the etching of carbon contaminants from the Mo(110) surface. The removal of the C islands (dark contrast in the LEEM) from the surface is obtained by dosing O₂ (2.9⋅10⁻⁹ Torr) and keeping the sample at 928 °C. STV=6.1 eV, FoV=15 μm².

 

The recipe to clean the Mo(110) surface consists of sputtering and annealing cycles at T=1000 °C in O₂ to remove carbon contamination. However, C atoms may also diffuse from the bulk to the surface of the Mo sample when cooling it down to T=907 °C thus impeding the complete removal of C. In the video, a real time LEEM imaging of the Mo(110) surface shows the reversibility of this process: the C islands (dark contrast) are removed at high temperature and they appear again when decreasing the temperature below 940 °C. STV=15 eV FoV= 15 μm².

 

Annealing the GaP(111) surface above 700 °C leads to the formation of Ga droplets. The video shows the real time MEM imaging of the surface for variable temperature. All the Ga droplets (dark contrast on the MEM image) propagate in the same direction across the surface leaving trails behind their passage and they become larger as they move. The width of the trail corresponds to the size of the droplet formation. During the travel, all droplets move perpendicular to the atomic steps on the wafer. In the movie all steps run horizontally, that is why the droplets move uphill and against the gravity force. STV=-0.2 eV FoV= 50 μm².