Photoelectron scattering in a p-GaN(Cs,O) photocathode

Photoelectron scattering in a p-GaN(Cs,O) photocathode was studied by photoelectron emission spectroscopy at low temperatures. It has been experimentally established that the transfer of photoelectrons from the bulk of a p-GaN(Cs,O) photocathode to vacuum is accompanied by the emission of a cascade of optical phonons in the bulk and at the GaN-vacuum interface. Based on how the high-energy features of the photoelectron energy distribution shift with the photon energy, we find m(hh)/m(0) = 2.3 +/- 0.3.