Hydrogen passivation of nitrogen-related energy levels in ZnSe and ZnSSe grown by MBE

In previous work we reported the observation of three hole traps in N-doped ZnSe and ZnSxSe1-x films grown by MBE. We attributed a trap T1 at E-v + 0. 11 eV in ZnSe to a dominating nitrogen acceptor, but traps T2 at E-v + 0.46 and T3 at E-v + 0.56 eV to the N-doping process. In the present study we i nvestigated the effect of hydrogenation on these hole traps. We found that samples with net acceptor concentrations less than few times 10(16) cm(-3) become highly resistive after the hydrogenation. In samples which remained conductive the hydrogenation caused a decrease in the DLTS peak heights of T2 and T3 within 0.4-0.5 mu m from the surface. In samples with net accepto r concentration around 2-5 x 10(16) cm(-3) we also observe a similar decrea se in the DLTS peak height of level T1 and net charge density which shows i ts role in the hole conductivity of the samples. Hydrogenation of samples w ith net acceptor densities in the 10(17) cm(-3) range did not affect the ne t charge density or height of T1 much. (C) 1999 Elsevier Science B.V. All r ights reserved.