Abstract
The semiconductor nanowire architecture provides opportunities for non-planar electronics and optoelectronics arising from its unique geometry. This structure gives rise to a large surface area-to-volume ratio and therefore understanding the effect of nanowire surfaces on nanowire optoelectronic properties is necessary for engineering related devices. We present a systematic study of the non-uniform optical properties of Au-catalyzed GaAs/AlGaAs core–shell nanowires introduced by changes in the sidewall faceting. Significant variation in intra-wire photoluminescence (PL) intensity and PL lifetime (τPL) was observed along the nanowire axis, which was strongly correlated with the variation of sidewall facets from {112} to {110} from base to tip. Faster recombination occurred in the vicinity of {112}-oriented GaAs/AlGaAs interfaces. An alternative nanowire heterostructure, the radial quantum well tube consisting of a GaAs layer sandwiched between two AlGaAs barrier layers, is proposed and demonstrates superior uniformity of PL emission along the entire length of nanowires. The results emphasize the significance of nanowire facets and provide important insights for nanowire device design.
Highlights
Semiconductor nanowires have been widely considered as one of the prime candidates for future devices, benefiting from their geometry that promises to overcome many of the challenges caused by lattice mismatch, and adding new functionality to devices (Lieber and Wang, 2007; Wong-Leung et al, 2019)
The results show that AlGaAs shell thicknesses increase with GaAs core diameters, with the thinnest shell thickness at 16 nm for nanowires with 50 nm GaAs core nanowires (Supplementary Figure 1)
The nanowire shows minimal tapering along its length, except in the region next to the Au nanoparticle sitting on the top
Summary
Semiconductor nanowires have been widely considered as one of the prime candidates for future devices, benefiting from their geometry that promises to overcome many of the challenges caused by lattice mismatch, and adding new functionality to devices (Lieber and Wang, 2007; Wong-Leung et al, 2019). For the core–shell nanowires, the growth resulted in an AlGaAs shell uniformly covering the GaAs core nanowire (Jiang et al, 2013).
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