600-nm wavelength range GaInP/AlInP quasi-quaternary compounds and lasers prepared by gas-source molecular-beam epitaxy

Abstract

GaInP/AlInP quasi-quaternary (QQ) compounds grown by gas-source molecular-beam epitaxy were systematically investigated. Quasi-quaternary properties were obtained with GaInP/AlInP short-period superlattices when the thickness of the AlInP layers was less than 3 ML. Equivalent band-gap values of QQ compounds were defined in terms of the layer thickness ratios of the GaInP and AlInP layers. Using GaInP/AlInP quasi-quaternary compounds, 607–640-nm wavelength QQ lasers with 20-nm QQ active layers were fabricated. Threshold current densities as low as 1.5 kA/cm2 were attained for QQ lasers emitting at 635 nm without the presence of strain or quantum-well effects.