Er doping in GaP was studied with metalorganic molecular-beam epitaxy employing a Knudsen cell for Er doping. Coherent growth of the Er-doped Gap layer was observed with relatively smooth surfaces up to Er concentration as high as similar to0.5%. Sharp 1.54-mum luminescence from Er3+ 4f-4f intra-shell transitions showed a weak temperature dependence and was observed up to room temperature. (C) 2002 Elsevier Science B.V. All rights reserved.