Photoinduced effects in UV laser melting of Si in UHV

The dynamics of laser heating and melting of Si in UHV is investigated by t ransient reflectivity with single pulse sensitivity. It is found that the h eating and melting dynamics cannot be accounted for by a model of heat flow using the thermal and optical properties of Si. Experiment and theory can be reconciled assuming significantly smaller thermal conductivity and heat capacity at all temperatures from ambient to melting. The melting temperatu re is also smaller. It is suggested that these specific parameters are rela ted to the photoinduced plasma. [S0031-9007(99)08806-7].