The luminescence of n-type InP single crystals grown from an In-solution is investigated. The electron concentration range is 1016-1019 cm-3. Weakly doped crystals exhibit two major emission bands at helium temperature, one (containing 4 emission lines) near 1.416 eV, a second at 1.38 eV. The 1.416 eV emission shifts to lower energy with increasing excitation intensity. Eventually stimulated emission is obtained in the energy range between 1.409-1.401 eV. The 1.38 eV band is due to donor-acceptor pair transitions. This is demonstrated by time resolved spectroscopy. A quantitative evaluation of the emission decay characteristic yields a Bohr-radius of 95Åfor the donor. At high doping levels, the two emission bands are interpreted as band-to-band and band-acceptor recombination. They show a pronounced Burstein-Moss shift to higher energy. Simultaneously, the band- acceptor transition gains in relative intensity and becomes very broad. Above 1018 electrons/cm3, it is the dominant emission band.