OPTICAL-DETECTION OF ELECTRON-NUCLEAR DOUBLE-RESONANCE AN A RESIDUAL DONOR IN WURTZITE GAN

Optically detected electron nuclear double resonance (ODENDOR) was mea sured in the 2.2-eV yellow luminescence band associated with a residua l donor in n-type unintentionally doped GaN. The ODENDOR lines are due to gallium and show a quadrupole splitting that can be described with an axial tenser. The quadnupole parameter was estimated to be q(Ga-69 )/h=1/2 Q(zz)=0.22 MHz. A hyperfine interaction for Ga-69 of approxima tely 0.3 MHz for the isotropic part and of approximately 0.15 MHz for the anisotropic part was estimated from the width of the ODENDOR lines . It is tentatively suggested that Ga interstitials are residual donor s.