Group III nitride core-shell nano- and microrods for optoelectronic applications

In the past few years, tremendous progress has been demonstrated on epitaxial growth and processing of group III nitride nano- and microrods (NAMs). This has also enabled the fabrication of optoelectronic devices based on NAMs as active elements. However, their efficiency is still far behind the performance of conventional GaN-based light emitting diodes (LEDs). This Review presents the most recent activities on the growth and processing of NAMs exhibiting a core–shell geometry, i.e. structures which consist of an active region shell layer wrapped around a three-dimensional (3D) core, which allow for an enormous increase in active area compared to planar technology. The most common growth approaches using metalorganic vapour phase epitaxy are described and evaluated with particular regard to their potential for solid state lighting applications. Examples for the unique properties of 3D NAMs are presented including their excellent crystalline quality. Furthermore, factors limiting the overall performance of 3D core–shell LEDs are revealed and the potential of overcoming these limitations are discussed. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)