Electron-beam-induced current and cathodoluminescence studies of thermally activated increase for carrier diffusion length and lifetime in n-type ZnO -: art. no. 162103

Temperature dependence of the minority carrier diffusion length and lifetime in bulk n-type ZnO was studied using electron-beam-induced current and cathodoluminescence techniques. The diffusion length was observed to increase exponentially over the temperature range from 25 degrees C to 125 degrees C, yielding activation energy of 45 +/- 2 meV. Concomitant decrease of the cathodoluminescence intensity for the near-band-edge transition was also observed. The activation energy determined by optical measurements was 58 +/- 7 meV. The larger minority carrier diffusion length and smaller luminescence intensity are attributed to the increased lifetime of nonequilibrium holes in the valence band at elevated temperatures. (C) 2005 American Institute of Physics.