<i>In situ</i> passivation of GaAsSb nanowires for enhanced infrared photoresponse.

Surface passivation of semiconductor nanowires (NWs) is important for their optoelectronic properties and applications. Here, thein situpassivation effect of an epitaxial InP shell and the corresponding photodetector performance is experimentally studied. Compared with the unpassivated GaAsxSb1-xcore-only NWs, the GaAsxSb1-x/InP core/shell NWs have shown much stronger photoluminescence and cathodoluminescence intensities. Correspondingly, the fabricated single GaAsxSb1-x/InP core/shell NW photodetector shows a responsivity of 325.1 A/W (@ 1.3 μm and 1.5 V) that is significantly enhanced compared to that of single GaAsxSb1-xcore-only NW photodetectors (143.5 A/W), with a comparable detectivity of 4.7×1010and 5.3×1010cm√Hz/W, respectively. This is ascribed to the enhanced carrier mobility and carrier concentration by thein situpassivation, which lead to both higher photoconductivity and dark-conductivity. Our results show thatin situpassivation is an effective approach for performance enhancement of GaAsxSb1-xNW based optoelectronic devices.