Surface band bending and surface conductivity of hydrogenated diamond

We establish a strict correlation between the total photoelectron yield spectra and the surface conductivity of hydrogenated diamond. The decomposition of the yield spectra into electron and exciton derived contributions requires an upward surface band bending to accompany surface conductivity, while an essentially flat band or downward band bending is observed after removing the surface conductivity by annealing in vacuum. Between the two competing models proposed for surface conductivity with a sheet hole density of 10 1 3 cm - 2 , these results favor the surface transfer-doping model strongly over the subsurface acceptor model.