Hydrogenation and annealing effects on the trapping times of the minority carriers in In-doped CdTe epitaxial layers grown on p-CdTe (211) substrates

Photoconductivity (PC) measurements on as-grown, annealed, hydrogenated, an d hydrogenated and annealed In-doped CdTe epitaxial films grown on p-CdTe ( 211) substrates by molecular beam epitaxy have been performed in order to i nvestigate the behavior of the trapping times of minority carriers in In-do ped CdTe films due to annealing and hydrogenation. The results of the PC de cay curve showed a slow component with a time constant of a few millisecond s and this behavior was related to the existence of deep trap levels corres ponding to minority carriers. The activation energies of the traps, as dete rmined from the temperature dependence of the PC decay times, were (E-v+0.3 5) and (E-v+0.43) eV for the as-grown and hydrogenated In-doped CdTe epilay ers, respectively. The trapping times of the minority carriers were signifi cantly reduced by the hydrogenation treatment. (C) 1999 American Institute of Physics. [S0021-8979(99)03114-X].