Self-assembled Nanostructures inside Indirect Bandgap Semiconductor by Using IR Femtosecond Double-pulses

Periodic nanostructures inside gallium phosphide are successfully induced by the IR femtosecond laser pulses. At present, in the case of a single component glass and an indirect bandgap semiconductor, we empirically found that such self-assembled nanostructures can be formed. Based on the previous researches, we assumed that the analogy of the longer relaxation time of a photoexcited electron between a glass and an indirect bandgap semiconductor is related to the nanostructure formation. In order to elucidate the formation mechanism of the periodic nanostructures inside semiconductor materials, we have compared the photoinduced structures in a gallium arsenide and a gallium phosphide. We have also observed that the periodic nanostructure embedded in gallium phosphide exhibits high electrical conductivities.