LIQUID-PHASE EPITAXIAL-GROWTH OF INGAP FOR RED ELECTROLUMINESCENT DEVICES

In this article we demonstrate the feasibility of growing n-AlGaAs/p-InGaP single heterostructures on a GaAs substrate by liquid-phase epitaxy. Good quality InGaP epitaxial layers as characterized by X-ray diffraction, Nomarski phase contrast microscope, photoluminescence and Hall measurements are obtained by optimizing the Ga liquid composition of 0.0093-0.0097 mole fraction in the InGaP growth solution. The minimum transition width of 200 angstrom at the AlGaAs-InGaP heterointerface is obtained by growing the AlGaAs epitaxial layer onto the as-grown InGaP layer with an 8-degrees-C super-saturation of AlGaAs growth solution. The p-n electrical junction is precisely controlled to be located at the metallurgical junction as measured by electron-beam induced current technique. Light-emitting diodes fabricated from the Al0.7Ga0.3As/In0.5Ga0.5P heterostructure have an emission peak wavelength of 660 nm. The forward-bias turn on voltage of 1.5 V with an ideality factor of 1.64 is obtained from the current-voltage measurements. The full-width at half-maximum of room-temperature electroluminescence and light output power at 100 mA of the uncoated red light-emitting diodes are 160 angstrom and 400-mu-W, respectively. An external quantum efficiency of 0.3% is two-fold higher than those previously reported.