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 the 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 entire composition range investigated. The band gap derived from the luminescence excitation spectra corresponds to that of a fully relaxed InGaP film with no residual strain, which is confirmed by the Raman measurements. Light-emitting diodes with peak (300 K) emission centered at less 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 the InyGa1-yP system and has lattice mismatch from the GaAs substrate of 1%.