Abstract
Radical-assisted metal organic chemical vapor deposition of ZnSe thin films was performed using nitrogen trifluoride (NF3) as the co-reactant and source of nitrogen atoms. The growth rate showed a gradual increase with an increase of NF3 flux. The photoluminescence (PL) spectra of all the films showed the intense donor-acceptor pair (DAP) emission and the weak excitonic emission bound to neutral nitrogen atom pair (I1N-N). The results gave a direct evidence of N-doping in ZnSe thin films by radical-assisted MOCVD. The I1N-N emission intensity was dependent upon NF3 flux, indicating that non-radiative recombination centers were introduced at high NF3 flux. In case of the growth at high NF3 flux, the additional PL emission was observed at 2.4-2.5eV, the intensity of which decreased after the heat-treatment. The result suggests that the heat-treatment might be effective for quality enhancement through the decrease of undesirable defects and nonradiative recombination centers.
