Abstract:
Cuprous oxide (Cu2O) is a metal-oxide semiconductor with a band gap of about 2 eV,
which has attracted interest because of its potential applications in solar energy
conversion, catalysis and gas sensors. Such applications and emerging applications of
Cu2O thin films in other areas make it worthwhile to study the electro-optical
characteristics of Cu2O thin films extensively (Olsen et al., 1982). Fabrication of Cu2O
thin films using electrodeposition is advantageous over the other techniques as this
process includes low temperature, economy, simplicity and possibility of making large
area thin films. Also, adjusting the deposition parameters during electrodeposition allows
the conductivity type and the film morphology to be controlled as required (Lee et al.,
2006; Rai 1988).
The currently reported photovoltaic conversion efficiencies of good Cu2O based solar
cells have remained in the range of 1-2 % which is far below the theoretical value. Barrier
height measurements in various Schottky barrier solar cells have shown that values are
always in the range 0.7-0.9 eV regardless of the substrate which forms the back contact of
the cell. This is believed to be the principal cause of the low performance of the Cu2O
Schottky barrier solar cells (Abdu, 2009). Therefore, the selection of a better substrate
(metal or condcutive coating) for the junction formation is considered to be the most
important factor. Metals with high work functions such as Ni and Pt, are considered to be
such candidates for the n-Cu2O Schottky junction solar cells. Cost-wise Ni can be
considered a better material as opposed to Pt which is highly expensive.
