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Selected results of department 26

Nanocrystallization of silicon using AFM

We are researching alternative ways of preparing Si nanocrystals, here by crystallizing amorphous silicon using sharp tip in atomic force microscope (AFM). At pre-defined positions in the thin film of amorphous silicon, flowing electrical current creates microscopic pits exhibiting high conductivity. The high conductivity is attributed to the formation of silicon crystallites. The whole text »

New Insight on Atomic-Resolution Frequency Modulation Kelvin Porbe Force Microscopy Imaging of Semiconductors

We provide new insight into atomic contrast obtained using Kelvin Probe Force Microscopy based on both experimental and theoretical analysis. We proved that the atomic contrast is not an artefact, but it is based on underlying physics. In particular, we performed a set of complex computer simulations of tip-sample interaction between the scanning probe and the surface. The simulations showed a change of the charge density redistribution and consequently the surface dipole due to the formation of the chemical bond between a probe and surface atoms. The whole text »

Measuring of individual grains in micro-crystalline silicon

  1. left image: topography of grains measured by ambient atomic force microscopy (AFM)
  2. right image: simultaneously measured map of local conductivity.
We are measuring the current flowing from the AFM tip through the sample to the bottom electrode.
The whole text »

Surveying of properties of thin films for solar modules

Solar modules based on thin films reach several times faster energy return than the common wafer-based modules. Millions of such modules m2 are produced annually in the world. Best results so far are expected from nanostructural thin films, so called micro crystalline or nano crystalline silicon, however for these products we have to find new methods for measuring their properties with resolution down to nanometres. The whole text »