The photoluminescence (PL) properties of in-situ Er doped GaN prepared by metalorganic molecular beam epitaxy (MOMBE) have been investigated. The GaN:Er films were grown on sapphire or silicon substrates. The oxygen and carbon background concentrations in the films were measured to be in the order of ∼10 20 and ∼10 21 cm −3, respectively. Both types of GaN:Er samples showed intense 1.54 μm PL at room temperature under below-gap optical excitation. For above-gap excitation, a greatly reduced Er 3+ luminescence intensity was observed. Pump intensity dependent PL studies revealed that the Er 3+ excitation efficiency under above-gap excitation is roughly a factor of ∼30 smaller compared to below-gap excitation. Based on the efficient Er 3+ below-gap excitation process a hybrid GaN:Er/sapphire/InGaN LED was developed.