Electrical and optical properties of ITO:Ca composite thin films for TEOLED cathode

ITO:Ca composite thin films were deposited on glass substrate by the rf magnetron co-sputtering method with various numbers of Ca chips and oxygen partial pressures. The carrier concentration of the ITO:Ca thin film was 7 × 1020 cm− 3 when the number of Ca chips was 4 at an oxygen partial pressure of 1.4%. The sheet resistance and optical transmittance of the ITO:Ca thin films were 68.2 Ω/sq. and 87%, respectively. The work function of the ITO:Ca thin films with 8 Ca chips was changed from 4.6 eV to 5.0 eV when the oxygen partial pressure was increased from 0.8% to 2.2%. When the oxygen partial pressure was 1.2%, a low work function of 4.6 eV was obtained for the ITO:Ca thin films.