Electrical resistance and the time-dependent oxidation of semicontinuous bismuth films

Abstract

We report on the electrical resistance and time-dependent oxidation of thin (≲90 Å) semicontinuous bismuth films. An increase in the room temperature sheet resistance with exposure to air is correlated with the growth of insulating Bi2O3 at the surfaces and internal boundaries between bismuth particles. For short oxidation times t, the resistance increases as R⧠ ∝t1/2, consistent with a parabolic oxide growth law. At longer times the resistance follows the classical percolation law R⧠∝‖tc−t‖−μ, where tc is a critical exposure time and μ≂1.3 is a critical exponent for two-dimensional systems.