Heavily phosphorus or gallium‐doped silicon was grown by liquid‐phase epitaxy and studied by photoluminescence. For the phosphorus‐doped samples grown from In(P) solution, recombination of free electrons to compensating In acceptor levels was observed besides the free electron‐free hole band‐to‐band emission. The gallium‐doped samples showed a luminescence spectrum similar to the one observed in bulk‐dopedp‐type material, indicating a good crystalline quality and low compensation in these samples. The band‐gap shrinkage was found to be larger in heavily gallium‐doped than in boron‐doped silicon, indicating a dependence of this shrinkage on the chemical nature of the dopant atoms.