SCANNING TUNNELING MICROSCOPY OF THE ELECTRONIC-STRUCTURE OF CHEMICALVAPOR-DEPOSITED DIAMOND FILMS

Scanning tunneling microscopy has been used to characterize the electr onic structure and surface morphology of diamond films grown using the hot filament and microwave plasma chemical vapor deposition technique s. We observe a significant difference between the current-voltage (I- V) curves for the two types of films. The I-V curves for the hot-filam ent grown films are characterized by a well-defined zero-current regio n from which a surface band gap of 4.1 eV is measured. The I-V curves for the microwave plasma grown films exhibit a rectifying behavior whi ch can be modeled by surface band bending. We compare the surface dens ity of states obtained from the I-V curves with those obtained from x- ray photoelectron and appearance potential spectroscopies.