Dynamics of femtosecond laser-induced melting and amorphization of indium phosphide

7 pages, 5 figures.-- PACS: 64.70.Dv; 81.30.Fb; 61.80.Ba; 78.66.Fd; 61.82.FkLaser-induced melting and resolidification of single-crystalline indium phosphide (InP) upon irradiation with 150 fs laser pulses at 800 nm has been investigated by means of real-time-reflectivity measurements with subnanosecond time resolution. Melting of the surface is observed to occur very rapidly on a time scale shorter than our experimental resolution while the lifetime of the liquid phase is several tens of nanoseconds. As a result of the subsequent rapid solidification process, a thin layer of amorphous material with a thickness of several tens of nanometers is formed on the surface. The formation of this amorphous layer has been observed for every fluence above the melting and below the ablation threshold. The evolution of the reflectivity has been modeled for several different solidification scenarios and compared to the experimental results. This comparison shows that solidification proceeds interfacially from the solid interface towards the surface. A lower limit for the critical solid-liquid interface velocity for amorphization in this compound semiconductor has been estimated to be in the range of 1–4 m/s.This work has been partially supported by the EU in the frame of the TMR Project XPOSE (Grant No. HPRN-CT- 2000-00160). S.M.W. acknowledges the funding in the frame of the same project. J.B. acknowledges the funding of the CSIC through a contract in the frame of the I3P programme (Ref. I3P-PC2002), co-funded by the European Social Fund.Peer reviewe

Dynamics of femtosecond laser-induced melting and amorphization of indium phosphide

7 pages, 5 figures.-- PACS: 64.70.Dv; 81.30.Fb; 61.80.Ba; 78.66.Fd; 61.82.FkLaser-induced melting and resolidification of single-crystalline indium phosphide (InP) upon irradiation with 150 fs laser pulses at 800 nm has been investigated by means of real-time-reflectivity measurements with subnanosecond time resolution. Melting of the surface is observed to occur very rapidly on a time scale shorter than our experimental resolution while the lifetime of the liquid phase is several tens of nanoseconds. As a result of the subsequent rapid solidification process, a thin layer of amorphous material with a thickness of several tens of nanometers is formed on the surface. The formation of this amorphous layer has been observed for every fluence above the melting and below the ablation threshold. The evolution of the reflectivity has been modeled for several different solidification scenarios and compared to the experimental results. This comparison shows that solidification proceeds interfacially from the solid interface towards the surface. A lower limit for the critical solid-liquid interface velocity for amorphization in this compound semiconductor has been estimated to be in the range of 1–4 m/s.This work has been partially supported by the EU in the frame of the TMR Project XPOSE (Grant No. HPRN-CT- 2000-00160). S.M.W. acknowledges the funding in the frame of the same project. J.B. acknowledges the funding of the CSIC through a contract in the frame of the I3P programme (Ref. I3P-PC2002), co-funded by the European Social Fund.Peer reviewe