Very low threshold current density (Al)GaInAs/Al(Ga)InAs laser structures grown by atmospheric pressure MOVPE

The growth of (Al)GaInAs/Al(Ga)InAs structures of high quality for laser devices using metalorganic vapor-phase epitaxy (MOVPE) at atmospheric pressure is described. SeH₂ and DEZn have been used as the dopant precursors. Se is an appropriate dopant for the n-type confinement layers of lasers, showing a distinctly higher electrical activation in AlInAs than Si. Zn is superior to Mg as a dopant for the p-type confinement layers of lasers as its apparent diffusion coefficient is about one order of magnitude lower than that of Mg in AlInAs. Broad-area double-heterostructure (DH) lasers (device length=800 μm) operating at 1.66 μm and 1.55 μm are shown to have I_th values as low as 2.3 kA cm² and 1.5 kA/cm², respectively. With broad-area separate-confinement-heterostructure multiple-quantum-well (SCH-MQW) lasers (device length=800 μm) emitting at 1.524 μm, threshold current densities as low is 0.92 kA/cm² can be achieved