Current image tunneling spectroscopy of chemical vapor deposited diamond films

The effects of boron doping on the electron field emission properties of diamond films were examined using current image tunneling spectroscopy in atomic force microscopy (AFM). Tunneling current-voltage (I-t-V) characteristics measured by AFM indicate that incorporation of boron species induces the presence of the impurity state. The films doped with 3 sccm boron (B3) possess the smallest emission barrier (E-b = 1.65 eV) and the largest emission ratio (eta=38%) among the boron-doped diamond samples. Therefore, B3 diamond films can be turned on at the smallest electric field (E-0 = 8.8 V/mum), exhibiting largest field emission capacity (J(e) = 250 muA/cm(2)). Restated, the electron field emission behavior of diamond films is closely related to the formation of impurity states due to boron doping. (C) 2003 American Vacuum Society.