Terahertz emission from CuO nanowires synthesized through thermal oxidation of Cu foils

• Main Authors: Husay, Horace Andrew, Balgos, Maria Herminia, Tumanguil, Mae Agatha, Muldera, Joselito E., Estacio, Elmer S., Salvador, Arnel A., Somintac, Armando S.
• Format: text
• Published: Animo Repository 2015
• Subjects: Nanowires; Copper—Oxidation; Terahertz spectroscopy; Physics
• Online Access: https://animorepository.dlsu.edu.ph/faculty_research/8133
• Institution: De La Salle University

We demonstrate terahertz (THz) emission from cupric oxide nanowires (CuO NWs) synthesized through thermal oxidation of Cu foils in ambient air by heating the foils in a hotplate for two hours at 300, 350, 400, and 450 °C. Scanning electron microscopy revealed the changes in the morphology of the foils; from the formation of a film composed of grains at 300 and 350 °C to the formation of NWs at 400 and 450 °C. The NWs were seen to have densities and dimensions that vary depending on the oxidation temperature. X-ray diffractometry showed that the grains that form at 300 and 350 °C were composed of a mixed phase of Cu2O and CuO, while the CuO NWs were observed to crystallize at temperatures greater than 400 °C. THz time domain spectroscopy (THz-TDS) showed that the foils containing CuO NWs were observed to emit THz radiation. It was further shown that increasing the density and dimensions of the NWs enhances the transient photocurrent generated throughout the length of the NWs, resulting in a stronger THz emission.