Gas source molecular beam epitaxial growth and characterization of 600–660 nm GaInP/AlInP double-heterostructure lasers

Abstract

Gas source molecular beam epitaxy (GSMBE) is one of the most promising technologies for growing AlGaInP which is an important compound system for realizing high performance 550–700 nm range visible light emitting devices. In this paper we review the investigations carried out for GSMBE-grown AlGaInP crystals and visible lasers, involving several results for AlGaInP systems grown by metal-organic chemical vapour deposition. First of all, we investigated growth conditions of high optical-quality GaInP by GSMBE, followed by the fabrication of 600 nm range GaInP/AlInP double-heterostructure lasers. To improve the lasing performances, various techniques described in this paper have been investigated. (GaInP) 2.5/(AlInP) 2.5 short-period superlattices were utilized to suppress the non-radiative recombination at the interface between the active and AlInP cladding layers. These superlattices were also used as the superlattice barriers in multiple-quantum-well active layers. The effect of misoriented GaAs substrates from the (100) surface toward the [011] direction on material properties and lasing performances was systematically investigated. It was clarified that the spontaneous crystal ordering was suppressed and the Al-related non-radiative recombination was reduced. Also, this substrate misorientation effect was effective in enhancing the electrical activity of Be in AlInP cladding layers with a resultant drastic reduction in threshold current density. The introduction of novel multiple-quantum-barrier structure into lasers was also investigated, for the first time; this was very effective in reducing the carrier overflow from the active layer. As a result, a drastic improvement in lasing performance of 660 nm lasers was obtained. Finally, a new shutter control method to form a strained quantum well layer without growth interruption is presented.