Synthesis and Characterization of a p-type nanosemiconductor

Delafossite, CuAlO2, is a transparent p-type nanosemiconductor material with a band gap of above 3 eV and has a wide variety of applications such as optoelectronics device technology, refrigeration of electronic device, water photoelectrolysis, thermoelectric material, and light emitting diodes (LEDs) [1-3].Although various techniques have been used for the preparation of delafossite, CuAlO2, such as solid state reaction between CuO and Al2O3 above 1000 °C for 24hr, ion exchange of α-LiAlO2 with CuCl, and sol-gel method [4,5] there is limited number of reports on the preparation of bulk and nano-size CuAlO2. It is well recognized that the prolonged and high temperature processes changes grain size, and resulted in formation of agglomerated powders and significantly affects the thermoelectric properties. Therefore, processing CuAlO2 powder at lower temperature should be beneficial. In the present work, we report on the preparation of nanodelafossite CuAlO2 by conventional and also microwave heating of copper oxide and aluminum nitrate. The prepared nano-size CuAlO2 powders were characterized by X-ray diffraction (XRD), and scanning electron microscopy (SEM