Time- and angle-resolved photoemission study of InP(110)

Time- and angle-resolved ultraviolet photoemission spectroscopy was used to study electron dynamics in the picosecond time domain on photoexcited InP(110) surfaces. A transient population in the normally unoccupied C₃ surface state was observed in the photoemission spectra following excitation of a bulk carrier plasma. Electron energy and momentum distributions in the C₃ surface state were independently followed as the population decayed. Observed nonexponential decays of approximately 300 psec duration can be attributed to equilibration of the surface and bulk populations on a subpicosecond time scale, followed by diffusion of the bulk plasma away from the surface. Band-dispersion parameters for the C₃ surface band were obtained. The C₃ band minimum was found to lie 1.47 eV above the valence-band maximum at {Γ}{}, the center of the surface Brillouin zone, and the surface effective mass was found to be anisotropic with values of 0.20{≤}m*/mₑ{≤}0.24 along the 〈1{}10〉 direction, and 0.10{≤}m*/mₑ{≤}0.15 along the 〈001〉 direction.