Band structure of indium phosphide from near-band-gap photoemission

Energy analysis of the electrons photoemitted from p-type doped (100) InP crystals is performed with 20-meV resolution, at 120 K. The samples are activated to low electron affinity. Laser excitation in the photon energy range 1.96h3.53 eV is used. The locations of the subsidiary minima L6 and X6 of the first conduction band and X7c of the second one are unambiguously measured (respectively, 0.67, 0.90, and 1.18 eV above the bottom of the conduction band). The energy dispersion of the three upper valence bands and of the first conduction band is probed over a large portion of the Brillouin zone. These experimental results are accurately described in the framework of the kp Kane model and the value of the spin-orbit-split-band mass m7=(0.190.01)m0 (where m0 is the free-electron mass) is directly obtained.