Light in concert with force reveals how materials become harder when illuminated

A team of researchers from Nagoya University, Japan, and Technical University of Darmstadt have developed a technique for quantitatively studying the effect of light on nanoscale mechanical properties of thin wafers of semiconductors or any other crystalline material. The group has found clear evidence that propagation of dislocations - slippages of crystal planes - in semiconductors is suppressed by light. The likely cause is interaction between dislocations and electrons and holes excited by the light.