Mm. Bataineh et Dk. Reinhard, AN IMPEDANCE SPECTROSCOPY INVESTIGATION OF POLYCRYSTALLINE DIAMOND FROM DC TO 1 GHZ, DIAMOND AND RELATED MATERIALS, 6(11), 1997, pp. 1689-1696
Impedance spectroscopy methods were used to study electrical conductio
n in diamond over a frequency range from de to 1 GHz. Both thick-film,
free-standing samples (400 mu m thickness) and thin-film (3-6 mu m th
ickness) samples on silicon were investigated. Experimental results fi
t well to an electrical model, which includes both a hopping conductio
n path, and a parallel path, which includes the capacitive nature of p
otential barriers at grain boundaries. For finer-grain, thin film samp
les, the data indicate that hopping plays the larger role. However, th
is was not the case for the larger-grain, thick film samples for which
the grain boundary path dominated the frequency-dependent admittance
between 1 and 100 MHz. The contact resistances, although small, play a
non-trivial role in the impedance model at high frequencies, in the o
rder of several hundred megaHertz. (C) 1997 Elsevier Science S.A.