III-V compound semiconductor nanowires (NWs) have drawn much attention as nanoscale light sources for integrated photonics due to their nanoscale size, good optical properties and strain relaxation feature enabling the monolithic growth on lattice mismatched substrates. In particular, NWs grown by selective area epitaxy (SAE) technique have many advantages such as controllability of their size and position, high uniformity in diameter and length, as well as complementary metal-oxide-semiconductor (CMOS) process compatibility, facilitating their integration with Si based electronic technologies. With suitable wavelength ranging from 1.3 to 1.6 μm and lattice match of constituent materials, InGaAs/InP quantum wells (QWs) have been being widely used for optical communication applications. However there has been limited understanding on the growth of InGaAs/InP QWs in nanowire architecture and their application for lasers or LEDs. In this work, we present a new crystal facet engineering strategy to achieve SAE growth of highly uniform InGaAs/InP multiple quantum well nanowire arrays by metalorganic chemical vapour deposition (MOCVD) technique, and the demonstration of high speed, multi-wavelength nanowire LEDs at telecommunication band with an in-depth investigation of their geometry related device properties.