Experimental test for the conductivity properties from the Casimir force   between metal and semiconductor
  The experimental investigation of the Casimir force between a large metallized sphere and semiconductor plate is performed using an atomic force microscope. Improved calibration and measurement procedures permitted reduction in the role of different uncertainties. Rigorous statistical procedures are applied for the analysis of random, systematic and total experimental errors at 95% confidence. The theoretical Casimir force is computed for semiconductor plates with different conductivity properties taking into account all theoretical uncertainties discussed in literature. The comparison between experiment and theory is done at both 95 and 70% confidence. It is demonstrated that the theoretical results computed for the semiconductor plate used in experiment are consistent with data. At the same time, theory describing a dielectric plate is excluded by experiment at 70% confidence. Thus, the Casimir force is proved to be sensitive to the conductivity properties of semiconductors. 
F. Chen, U. Mohideen, G. L. Klimchitskaya, V. M. Mostepanenko