Deep state in the bandgap and photoluminescence of Zn_1-xMn_xO

The impurity absorption in Zn1-xMnxO is formed by dipole allowed p-s transitions from deep antibonding p-d hybrid (pdh) state to the conduction band. In this paper, photoluminescence of Zn1-xMnxO single crystals was investigated in the temperature range of 7-340 K at laser excitation with the energy of 3.06 eV. Intensive photoluminescence band was observed in the energy region of 2.40-1.6 eV with the maximum at the energy of 2.17 eV. The energy of the impurity center ionization 2.35 eV was determined in this paper. The analysis of photoluminescence band form, and also close coincidence of its headline and impurity band edge allow us to interprete this band as a result of radiative dipole allowed s-p transitions from the conduction band to impurity pdh level.