Liquid-phase epitaxial growth and characterization of InGaAsP layers grown on GaAsP substrates for application to orange light-emitting diodes

Abstract

Growth and characterization of Ga0.65In0.35P orange lightemitting diodes by metalorganic vapor-phase epitaxy Growth and characterization of singleheterostructure AlGaAs/InGaP red lightemitting diodes by liquidphase epitaxyThe growth conditions of undoped InGaAsP layers grown on GaA~~rPu,s, substrates 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 2X1016 cmm3. Room-temperature carrier concentrations in the range of 1.8X10r7-3.4X101* cmv3 for n-type dopant and 1.6Xl.0f7-2.8X1018 cm 'a for p-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 GaAs0.61P0.39 substrate 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 the I-V measurements. 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. 0 1995 American Institute of Physics.