  Photonic crystal (PhC) cavities are promising candidates for Si photonics
integrated circuits due to their ultrahigh quality (Q)-factors and small mode
volumes. Here, we demonstrate a novel concept of a one-dimensional hybrid
III-V/Si PhC cavity which exploits a combination of standard
silicon-on-insulator technology and active III-V materials. Using
template-assisted selective epitaxy, the central part of a Si PhC lattice is
locally replaced with III-V gain material. The III-V material is placed to
overlap with the maximum of the cavity mode field profile, while keeping the
major part of the PhC in Si. The selective epitaxy process enables growth
parallel to the substrate and hence, in-plane integration with Si, and in-situ
in-plane homo- and heterojunctions. The fabricated hybrid III-V/Si PhCs show
emission over the entire telecommunication band from 1.2 {\mu}m to 1.6 {\mu}m
at room temperature validating the device concept and its potential towards
fully integrated light sources on silicon.
