Effective Passivation of InGaAs Nanowires for Telecommunication Wavelength Optoelectronics

摘要

Catalyst-free InGaAs nanowires are promising building blocks for optoelectronicdevices operating at telecommunication wavelengths. Despite progress,the applications of InGaAs nanowires remain limited due to their highdensity of surface states that degrade their optical properties. Here, InGaAsnanowires with superior optical properties are achieved by effectively suppressingtheir surface states with an InP passivation shell. Optimal InP shellgrowth conditions and thickness to maximize the minority carrier lifetimeare identified. The photoluminescence intensity of these passivated InGaAsnanowires is up to three orders of magnitude higher than that of their barecounterparts. Moreover, a long minority carrier lifetime of up to ≈13 ns ismeasured with these passivated nanowires at room temperature. Optimalpassivation of InGaAs nanowires with an emission wavelength of 1530 nmresults in an ultra-low surface recombination velocity of ≈280 cm s~(?1). In additionto the shell, the crystal structure of these nanowires plays an importantrole in the luminescence intensity. Combined cathodoluminescence mappingand high-resolution transmission electron microscopy along the nanowiresreveal significantly lower emission intensities in wurtzite predominant sectionsof the nanowires than zinc blende predominant ones.These insights onthe optimal passivation of InGaAs provide directions for engineering highperformancenanoscale-devices in the telecommunication wavelength.