Photoelectric Emission and Interband Transitions of GaP

Abstract
The photoelectric yield spectrum and energy distributions of the emitted electrons have been measured at photon energies between 3.0 and 6.0 eV on the (110) surface of GaP. Preparation of the emitting surfaces included cleavage in ultrahigh vacuum and deposition of various amounts of cesium. The results are interpreted in terms of direct optical transitions and compared with other optical properties. Photoelectric emission furnishes evidence supporting the interpretation of reflectivity data by Bergstresser et al., and Wolley et al., and the electro-reflectance studies of Cardona and co-workers. Good agreement is found with the band structure of GaP computed by Cohen and Bergstresser.