Abstract
High quality boron doped
diamond electrodes have been fabricated with a wide range of boron doping
levels.
Ohmic diamond-titanium
contacts were made by depositing the diamond films on top of a partially
titanium coated silicon substrate. The electrical behaviour of these contacts
was measured and compared to traditional top contacts. These novel titanium
undercontacts provided a superior response and also significantly simplified
the processing required to fabricate low doped diamond electrodes.
Reversible electrochemistry
was seen on highly doped diamond electrodes.
AC impedance measurements
have shown that electron transfer across the interface occurs via a surface
state.
The electrochemistry of low
doped diamond films has been shown to be highly dependent on surface
termination. Hydrogen terminated diamond electrodes have exhibited reversible
behaviour while oxygen terminated diamond electrodes have shown limited
cathodic currents. These results are discussed in relation to a surface state
mediated electron transfer mechanism.
Photocurrent spectroscopy;
and intensity modulated photocurrent spectroscopy (IMPS) studies were
performed.
Polycrystalline diamond with
low boron doping levels was shown to behave as a p-type semiconductor.