Laser-induced electronic desorption from InP surfaces studied by femtosecond nonresonant ionization spectroscopy - art. no. 035414

Laser-induced desorption from clean surfaces of InP(110)-(1x1) and InP(100) -(4x2) has been studied for laser fluences well below melt and ablation thr esholds. For detecting desorbed neutral species simultaneously with hi,oh s ensitivity, we used femtosecond nonresonant ionization spectroscopy with a detection limit as low as the order of 10(-7) monolayers per pulse. Species desorbed are P, P-2, and In, the relative yields of which are strongly dep endent on the surface structures, and the efficiencies of desorption for th e three species are superlinear with respect to the excitation intensity. D esorption yields of all species decrease with increasing number of laser sh ots on the same spot, suggesting desorption from preexisting surface defect sites. Time-of-flight measurements for P, P-2, and In from InP surfaces re vealed that the peak flight time and the velocity distribution did not depe nd on the excitation intensities. The mechanism of the laser-induced desorp tion is discussed based on these results.