Time dependence of electrical resistance and ESR defects in surface conductive layer on diamond films

Electrical resistance and paramagnetic defects in the surface conductive layer on the diamond films are measured by two-probe and electron spin resonance (ESR) method before and after exposing to air, and after thermal treatment. When the diamond film surface is exposing to air, the decrease in electrical resistance and the increase in ESR signal due to the carbon dangling bond in the diamond films were observed, The spin density in surface conductive layer is estimated similar to 9 X 10(15) cm(-3) from the increment of Pac-center. Furthermore, the intensity of Pac-center in the diamond films after the thermal treatment in O2 atmosphere was similar almost to that of the diamond films before exposing to air.