In spite of often superior properties, in terms of materials and device performance, compound semi- conductors like GaAs and GaN often encounter difficulties in market acceptance, in most cases due to issues of fabrication costs. Nanowires (NWs) constitute a special case due to the opportunities they offer to form highly ideal one-dimensional materials that can be designed into three-dimensional heterostructures via axial as well as radial heterostructures, furthermore with the ability as a technology to add compound semiconductor functionality to a silicon platform. I will structure this presentation into three areas:
(1) The development of high-quality GaN nanowires forming the basis for visible light-emitting diodes , primarily with application opportunities in displays, presently with a huge potential market in the areas of micro-LEDs for direct-view displays.
(2) Know-how gained from nitride NW nucleation offers a technology base for realization of relaxed and dislocation-free, c-oriented GaN and InGaN platelets and wafers  of significant value for directly driven RGB-emitting LEDs. Many applications areas for nitrides, for optics as well as RF/Power-applications, need higher quality, low dislocation density, wafers.
(3) Opportunities to drastically reduce cost of NW fabrication, based on a dramatically novel growth approach, which we have given the name Aerotaxy , by which NWs are grown in an aerosol phase, without use of substrates. I will discuss means by which such NWs may be processed into thin films, thus bridging the many orders of magnitude from discrete NW-devices to square-meter scale applications like for solar cells [4, 5].
 B. Monemar et al., “Nanowire-Based Visible Light Emitters, Present Status and Outlook”, Chapter 7 in Semiconductors and Semimetals 94, 227-271 (2016).
 L. Samuelson et al., “Gallium nitride nano-sized LEDs”, SPIE newsroom, 10.1117/2.1201603.006385 (2016).
 M. Heurlin et al., “Continuous gas-phase synthesis of nanowires with tunable properties”, Nature Vol. 492, 90 (2012)
 J. Wallentin et al., “InP Nanowire Array Solar Cells Achieving 13.8% Efficiency by Exceeding the Ray Optics Limit”, Science Vol 339, 1057 (2013)
 I. Åberg et al., “A GaAs Nanowire Array Solar Cell with 15.3% Efficiency at 1 sun”, IEEE Journal of Photovoltaics Vol. 6, 185 (2016)