Melting of a semiconductor crystal (InSb) with a short laser pulse (100 fs)

Time-dependent x-ray diffraction has been measured from laser-irradiated semiconductor crystals. Laser pulses with 100 fs duration and 800 nm wavelength excite the sample inducing phase transitions. 5 keV x-rays from the Advanced Light Source are diffracted by a sagittally-focusing Si (111) crystal and then by the sample crystal, InSb (111), onto an avalanche photodiode. By detecting individual pulses of synchrotron radiation, which have a duration of 70 ps, the diffracted intensity is observed to decrease because of photoabsorption in a disordered surfaced layer. Rocking curves measured after the laser irradiation show a tail, which results from a strained region caused by expansion of the crystal lattice.