Investigation of the Casimir force between metal and semiconductor test   bodies
  The measurement of the Casimir force between a large gold coated sphere and single crystal silicon plate is performed with an atomic force microscope. A rigorous statistical comparison of data with theory is done, without use of the concept of root-mean-square deviation, and excellent agreement is obtained. The Casimir force between metal and semiconductor is demonstrated to be significantly different than between two similar or dissimilar metals. 
F. Chen, U. Mohideen, G. L. Klimchitskaya, V. M. Mostepanenko