A research team of Ehime University paved a way to achieve unexplored III-V semiconductor nanostructures. They grew branched GaAs nanowires with a nontoxic Bi element employing characteristic structural modifications correlated with metallic droplets, as well as crystalline defects and orientations.
The finding provides a rational design concept for the creation of semiconductor nanostructures with the concentration of constituents beyond the fundamental limit, making it potentially applicable to novel efficient near-infrared devices and quantum electronics.
Nanowire is a rod-structure with a diameter typically narrower than several hundred nanometers. Due to its size and structure, it exhibits characteristic properties which are not found in larger bulk materials. The study of III-V semiconductor nanowires has attracted much interest in recent decades due to their potential application in nanoscale quantum, photonic, electronic, and energy conversion, and in biological devices, based on their one-dimensional nature and large surface to volume ratio.
The introduction of an epitaxial heterostructure facilitates control of the transport and electronic properties of such devices, showing the potential for realizing integrated systems based on III-V compounds and Si with superior electronic and optical functions.
III-V compound semiconductors are one of the highest in mobility and photon-electron conversion efficiency in existence. Among them, GaAs is a representative III-V compound semiconductor, which is utilized for high speed transistors, as well as high-efficiency near-infrared light-emitting diodes, lasers, and solar cells. Optical devices based on III-V GaAs suffer from intrinsic losses related to heat generation.
To circumvent this, the use of dilute bismide GaAsBi alloy with a nontoxic Bi element has recently gained attention because the introduction of Bi suppresses heat generation while increasing electron-light conversion efficiency. Therefore, incorporating dilute bismide GaAsBi alloy into nanowires is a rational approach for developing high-performance optoelectronic nanodevices.
Meanwhile, branched or tree-like nanowires offer an approach to increase structural complexity and enhance the resulting functions which in turn enable the realization of higher dimensionality structures, lateral connectivity, and interconnection between the nanowires.

Image Credit:  Ehime University

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