electrolyte

Most measurements in the ELYMAT are performed with hydrofluoric acid (HF) because of it's passivating properies on the silicon surface. Hydrofluoric acid

- dissolves a silicon oxid layer from the surface and

- saturates "dangling bonds" at the silicon surface,

which leads to an "allmost neglectable" surface recombination velocity S .

The absolut value of S and some other problemes concerning degeneration effect at a HF-Si-contact under illumination are topics of actual research.

Acidic acid is used instead of HF, if a silicon oxid layer should not be removed, e.g. to investigate the passivating properties of thermally grown silicon oxid.