Electron scattering study within the depletion region of the GaN(0001) and the GaAs(100) surface

Abstract

The energy distribution curves (EDCs) of photoelectrons emitted from the GaN(0001) negative electron affinity (NEA) surfaces are investigated along with GaAs(100) NEA surfaces. These experiments are performed at room temperature using 3.82eV laser excitation for GaN and 1.96eV laser excitation for GaAs. We find the main contribution to the total emitted current is the electrons that have lost an average energy of 310meV and 140meV, respectively, in the bandbending region (BBR). We propose that the origin of the energy loss as the electrons exit the solid is due to intervalley phonon scattering in the BBR (scattering of Γ electrons into the L–M valleys for GaN and L valley for GaAs). EDC studies on semiconductor NEA surfaces enable us to investigate the semiconductor electron transport property in the high-field region, which is established internally by the bandbending voltage at the surface.