The paper presents a critical analysis of Si light emitters made by ion implantation and describes novel concepts for IR light emitters based on silicon nanostructures that do not need Er doping. It is shown that dislocation networks which can be generated in a well controlled way by wafer direct bonding exhibit promising light emitting properties. The luminescence of the dislocation networks can be tailored by the choice of the misorientation of the bonded wafers. It is demonstrated that efficient D1 emission (1.55 μm) at 300 K or D3 emission (1.3 μm) can be obtained for specific misorientations. An enhancement of the luminescence is observed when applying a bias voltage across the network, caused by a changed occupation of the states at the network. Oxygen in the dislocation network is supposed to increase the intensity of the D1 luminescence. Si nanowires are discussed as another potential candidate for IR emitters. Among other lines, efficient luminescence around 1.55 μm is found at 300 K in nanowires. This emission line is attributed to extended defects within the nanowires.