Conclusions
In the present study, single phase of delafossite CuAlO2 (CAO)
was successfully synthesized by 600Wmicrowaving of 1:1 M ratio
Cu:Al of the mixture of Al(NO3)3$9H2O and Cu(CH3COO)2$H2O for
20 min. The CAO crystal was composed of quite distorted plates
with 200e350 nm thick. The optical properties were used to
determine its direct and indirect energy gaps of 3.9 eV and 2.9 eV,
respectively. The photoluminescence (PL) at room temperature
exhibited two peaks, corresponding to the indirect energy gap and
CuAl antisite. The electrical resistivity (r), thermal conductivity (k)
and Seebeck coefficient (S) of the CAO were decreased with the
increasing temperature, indicating a semiconducting behavior and
p-type TE crystal. The power factor and figure of merit (ZT) were
increased with the temperature to a maximum value at 1073 K.