Influence of Bi doping on the luminescence of ZnO phosphors

Abstract

Bismuth doped ZnO powder has been synthesized through solid-state chemical reaction and their optical properties investigated. A red emission band at 650 nm from bismuth has been observed and corresponding to the transition from 3P1 state to ground state (1S0). Two peaks at 384 and 432 nm in the excitation spectrum have been assigned to the field component of 3P1 state of bismuth. A weak energy transfer from the host bismuth was observed at room temperature. However, the relative intensity of the broad band from the host to the exciton lines was found to be 30 times weaker than that in ZnO. The reduction of the intensity of the broad band is ascribed to the decreasing of oxygen vacancies in bismuth doped ZnO. Doping with bismuth will greatly reduce the concentration of oxygen vacancies.