Silicon molecular beam epitaxy layers are characterised by photoluminescence. Low-energy ion doping with indium during growth has been exploited to obtain an In-doped silicon layer on a phosphorus-doped silicon substrate. The samples were grown over a range of growth temperatures, 550-850 degrees C, and the photoluminescence spectrum of the well known In-related shallow bound exciton line was detected for doping concentrations from 1*1016 to 1*1018 cm-3. Undoped silicon layers on boron-doped silicon substrates were used to study the effect of growth temperature. A previously unreported line at 884 meV is also studied.