In hydrogenated silicon, dangling bonds can be induced by (long) exposure to light. This causes a decrease in the photoconductivity of the material. (This is the most named explanation for the so-called Staebler-Wronski effect.) The mechanism of this is thought to be as follows: The photon energy is transferred to the system which causes the weak Si-Si bonds to break, leading to the formation of two bound radicals. The free electrons being localized and being very close together is an unstable state, so hydrogen atoms “move” to the site of the breakage. This causes the electrons to be delocalized further apart which is a more stable state. For a hydrogen content of around 10%, the dangling bonds from only a very small fraction of displaced hydrogen atoms can lead to observable EPR signal increases. The diffusion of hydrogen plays a key role in the process and explains why long illumination is required. It has been found that illumination under increased temperatures increases the rate at which light-induced dangling bonds form. This can be explained by the increased hydrogen diffusion.