Semiconductor nanowires are well known to have a great potential serving as building blocks in future generations of electronic and optoelectronic applications. Additionally, their geometry provides a good opportunity to test fundamental quantum mechanical phenomena. Even though significant advances have been made in the fabrication of nanowires, the use of gold nanoparticles as a seed has been a weak point of the production process, because gold significantly reduces the optical and electronic transport performance of the semiconductors. The physicist Anna Fontcuberta I Morral and her coworkers at the Technical University Munich (TUM) have now presented a novel method for the growth of GaAs nanowires and coaxial quantum heterostructures by molecular-beam epitaxy, avoiding the use of gold as a nucleation seed for the wires. The scientists have shown that the versatility of MBE can be used to selectively grow quantum heterostructures on the facets of the wires. Effectively, the wires act as the substrates for tubular quantum wells. The high crystal quality of the wells combined with their geometry could give rise to new phenomena and functional devices, such as multicolor light-emitting diodes.

Publication:  Prismatic Quantum Heterostructures Synthesized on Molecular-Beam Epitaxy GaAs Nanowires, Anna Fontcuberta i Morral, Dance Spirkoska, Jordi Arbiol, Matthias Heigoldt, Joan Ramon Morante and Gerhard Abstreiter, Small, 4, 899-903 (2008)