Passivation of dislocations in GaAs-on-Si

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Effects of PH_3/H_2 plasma passivation of GaAs grown on Si substrate have been investigated in detail. It is observed that both the surface phosphidation and hydrogenation can be realized simultaneously with a reduced plasma-induced damage by using PH_3/H_2 plasma exposure. The optical and electrical properties of GaAs on Si are effectively improved by PH_3/H_2 plasma exposure due to the passivation of bulk and surface defects-related nonradiative recombination centers by incorporation of hydrogen and phosphorous atoms. The experimental results show that the AlGaAs/GaAs recombination rate is reduced and the minority carrier lifetime is improved by the PH_3/H_2 plasma exposure. The PH_3/H_2 plasma exposed GaAs Schottky diodes on Si show an increase in the reverse breakdown voltage by a factor of about 1.6, and the as-passivated GaAs solar cell grown on Si shows an increase in the conversion efficiency from 15.9% to 18.6 % compared to that of the as-grown samples. The passivated GaAs dev … More ices on Si show outstanding thermal stability, which is probably due to the active participation of both H and P atoms in the PH_3/H_2 plasma passivation process. It is found that the high density of dislocations in GaAs/Si heteroepitaxial layers largely enhance the diffusion of phosphorous atoms during the PH_3/H_2 plasma exposure. Electron beam-induced current proved that the defect-related dark spot density was effectively reduced by adding P into the pure H_2 plasma In addition, PH_3/H_2 plasma exposure greatly increased the minority carrier properties and decreased the saturation current of GaAs pn junction structure grown on Si substrate. The incorporated P atoms strongly passivated the electrical states of residual dislocations in GaAs/Si solar cell. Significant spontaneous emission enhancement is observed at the cavity mode for the hydrogen plasma passivated AlGaAs/GaAs multi-quantum well samples., which results from the passivation of electrical activity of defect-related non-radiative deep centers and increased minority carrier lifetime. The defect passivation of InGaP grown on Si substrates was achived without dissociation of phosphorous from the surface by PH_3/H_2 plasma exposure. A significant enhancement of the photoluminescence intensity was observed, which is due to the hydrogenation defect-related nonradiative recombination centers. Less