Unexpected formation of a hierarchical structure in ternary InGaAs nanowires via "one-pot" growth.

The optoelectronic application of semiconductor nanowires largely depends on their nanostructures and related chemical characteristics. Although the spontaneously formed core-shell structure in ternary nanowires makes them often unpredictable, such versatile growth with varied chemical characteristics may open up opportunities for widening their applications. In this study, we present extraordinary phenomena observed during ternary InGaAs nanowire growth by molecular beam epitaxy. It was unexpectedly found that nanowires spontaneously formed the hierarchical structure during the growth: a pure core structure at the nanowire tip, a core-shell structure in the middle and a core-multishell structure in the bottom region. By careful electron microscopy investigations on nanowire growth at early stages, the growth mechanism of such a unique hierarchical structure was unveiled. This study provides new insights into ternary III-V nanowire growth with the hope of assistance in designing new nanomaterials and nanostructures for future optoelectronic devices.