The electroluminescence of PIN diodes with either strained SiGe/Si or Ge islands in the i-region have been investigated. For diodes with strained Si0.80Ge0.20 simulations have shown that the emission at 300 K can be improved if the thickness of the SiGe layer is increased. To overcome the thickness limitation due to the plastic relaxation selective epitaxy was used to deposit strained layers in small holes on patterned wafers. Indeed, for samples four times thicker than the critical thickness emission was observed to persist up to 300 K in contrast to thinner SiGe layers. Light emitting diodes with SiGe islands were shown previously to emit more light at low injection currents than diodes with strained SiGe layers due to the localization of carriers in the islands, while at higher injection levels the emission efficiency was comparable. Here it will be shown that the emission efficiency of diodes with islands could be increased, however, it is still lower than from diodes with thick SiGe layers.