Liquid-phase epitaxy has been used to grow four-layer GaAs/AlGaAs double heterostructures on Si substrates that had been precoated with GaAs by molecular-beam epitaxy and coating the remaining exposed parts of the Si wafer with SiO2. Direct growth of GaAs on Si by liquid-phase epitaxy is not feasible because of the dissolution of the Si substrate by the Ga melt. As with the other growth techniques, photoluminescence from the GaAs cap layer and electroluminescence from the 0.2-μm-thick GaAs active layer indicate the luminescence peaks are shifted to lower energy as a result of the tensile strain in the plane of the layers that is caused by the different thermal contraction of the GaAS and Si layers as the wafer is cooled from the growth temperature. Optically pumped stimulated emission is observed from the cap layer at 80 K. The efficiency of the electroluminescence from the active layer was low, indicating the p-n junction was displaced from the active layer due to the accidental excess doping resulting from a slight dissolution of the Si substrate in the Ga melt.