Identification of donor-related impurities in ZnO using photoluminescence and radiotracer techniques

Abstract

The results of photoluminescence measurements on ZnO implanted with stable and radioactive isotopes of Zn and Ga are presented. The donor-related exciton feature ${I}_{8}$ at $3.3600\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ is suggested to be due to bound exciton recombination at Ga donors. The ${I}_{1}$ line at $3.3718\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ is also likely to be due to Ga, and is attributed to ionized Ga donor bound exciton recombination. A feature at $3.3225\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ is observed following transmutation of radioactive Ga into stable Ge, and is attributed to Ge. Finally, a damage-related band is observed in the region of $1.8\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ when the recoil energy of the decay is capable of dislodging the host atoms from their respective lattice sites.