Photoluminescenece in P-Doped GaN

The luminescent properties of a blue emission band observed in P-doped GaN have been studied. The blue band is associated with isolated phosphorus atoms. The peak position and the half-width of this band are respectively 2.88±0.01 eV and 375±5 meV at 4.2 K. The peak position shifts monotonically to lower energies as the temperature increases. The temperature dependence of the half-width follows the simple configuration coordinate model. The energy of a local-mode phonon is 50±5 meV. This value agrees with the estimated value on the assumption that a nitrogen atom vibrates against its four nearest gallium atoms neighbours. From the temperature dependence of the emission intensity, the binding energy of a hole to a phosphorus atom is calculated as 280±10 meV.