PIEZOELECTRIC AND THERMOELECTRIC RESPONSE OF CUPROUS-OXIDE, CU2O

In the present work, polycrystalline samples of cuprous oxide, Cu2O, a re fabricated and their piezoelectric and thermoelectric properties ev aluated both as a polycrystalline material and as a composite material . Samples are prepared from electrical or analytical grade copper, in powder or solid form. Oxidation is carried out at 1050-degrees-C for 4 h. For the polycrystalline form, the Seebeck coefficient is about 1 m V/degrees-C. For the composite form, the coefficient is between 0.2 an d 0.4 mV/degrees-C. A piezoelectric response is also found. For the po lycrystalline material, the ratio between generated voltage and applie d voltage is about 0.2 at the resonance frequency. For the composite s amples, this ratio lies between 0.01 and 0.02. Resonance frequencies a re in the range 150 kHz-20 MHz, depending on the specific sample. The mentioned properties are not greatly dependent on grain size or grain orientation, probably due to the cubic structure of the Cu2O elemental cell.