Increase in photoluminescence of Zn-doped p-type InP after hydrogenation

The authors report on the effect of hydrogenation on the low-temperature (5.5 K) photoluminescence properties of Zn-doped p-type (p approximately 3*10¹⁸ cm^-3) InP substrates. The photoluminescence spectrum of the as-grown sample shows a Zn_In acceptor-related transition near the band-edge at 1.386 eV, a Zn-related PL band at 1.214 eV and a phosphorus vacancy V_P-related PL band at 1.01 eV. After hydrogenation of the samples by exposure to hydrogen plasma, which completely passivates the Zn_In acceptors over a depth of more than 1 mu m, the deep luminescence bands (1.214 and 1.01 eV) disappeared, with a concomitant approximately 2000-fold increase in the intensity of the near-band-edge emission. Such a large increase in radiative efficiency together with the elimination of the deep luminescence bands indicates hydrogen passivation of deep nonradiative centers in addition to passivation of shallow acceptors.