The growth conditions of undoped InGaAsP layers grown on GaAs0.61P0.39substrates and effects of Te and Zn‐doping on electrical and optical properties have been examined in detail. The narrowest full widths at half‐maximum (FWHM) of photoluminescence (PL) spectra were measured to be 40 meV at 300 K and 12 meV at 8 K for an undoped InGaAsP sample with a background electron concentration of 2×1016cm−3. Room‐temperature carrier concentrations in the range of 1.8×1017–3.4×1018cm−3forn‐type dopant and 1.6×1017–2.8×1018cm−3forp‐type dopant are obtained reproducibly. The 50 K PL spectra of Zn‐doped layers show three distinctive peaks and their relative intensities change with various hole concentrations. Visible light‐emitting diodes (LEDs) emitting at 619 nm and employing the InGaP/InGaAsP/InGaP double‐heterostructure (DH) grown on a lattice‐matched GaAs0.61P0.39substrate have been fabricated. The DH LEDs are characterized by current‐voltage (I‐V) measurement, electroluminescence (EL), light output power, and external quantum efficiency. A forward‐bias turn‐on voltage of 1.8 V with an ideality factor of 1.3 and a breakdown voltage of 16 V are obtained from theI‐Vmeasurements. The emission peak wavelength and FWHM of room‐temperature EL spectra are around 619 nm and 48 meV (15 nm) at 20 mA, respectively. The light output power of the bare diodes is as high as 0.32 mW at a dc current of 100 mA and an external quantum efficiency of 0.22% is observed. ©1995 American Institute of Physics.