P-Type transparent conducting copper-strontium oxide thin films for optoelectronic devices

摘要

p-Type thin films of copper-strontium oxide (Cu-Sr-O) have been deposited by e-beam evaporation technique on microscopic glass substrates. A study of optical, electrical and structural properties was performed on the thin films, varying temperature of annealing. Amorphous Cu-Sr-O films were obtained at low temperature. Partially polycrystalline films were obtained at high temperature of 550 °C with transparency over 72% at wavelength from 600 to 700 nm in the visible region and 83% in the near infrared region (λ = 1800:2500 nm). The optical band gap was estimated to be ~3.5 eV. The Seebeck coefficient measurements showed that the as-deposited films represented n-type conduction and with annealing temperature these films converted to p-type. The electrical conductivity measurements at room temperature of annealed films at temperature of 550 °C represented the best value about 2 S/cm. The other optical parameters such as refractive index, extinction coefficient, dielectric constant and cutoff wavelength were studied as a function of annealing temperature.