IN0.35GA0.65P LIGHT-EMITTING-DIODES GROWN BY GAS-SOURCE MBE

This paper describes the growth and optical characteristics of InyGa1- yP with 0.3 < y < 0.5, and the LED operation of p-i-n structures in th e same material system. The InGaP is grown using gas-source molecular beam epitaxy (GSMBE). The non-lattice-matched InyGa1-yP grown on GaAs using GSMBE has a specularly smooth surface morphology through the use of unique strained-layer superlattice (SLS) buffer. We have measured the luminescence, luminescence excitation, and Raman spectra of these undoped films and observe strong excitonic luminescence over the entir e composition range investigated. The band gap derived from the lumine scence excitation spectra corresponds to that of a fully relaxed InGaP film with no residual strain, which is confirmed by the Raman measure ments. Light-emitting diodes with peak (300 K) emission centered at le ss than 590 nm have been fabricated from p-i-n junctions in In0.35Ga0. 65P. This alloy is close to that with the largest direct band gap in t he InyGa1-yP system and has lattice mismatch from the GaAs substrate o f 1%.