GaInAsP/InP Multiple-Layered Quantum-Wire Lasers Fabricated by CH₄/H₂ Reactive-Ion Etching

GaInAsP/InP multiple-layered quantum-wire lasers with the wire width of 21 nm in the period of 100 nm were realized by CH 4 /H 2 reactive-ion etching followed by slight wet chemical etching and embedding growth by organometallic vapor phase epitaxy. A threshold current density as low as 1.45 kA/cm 2 was obtained with the cavity length of 980 µm. To our knowledge, this is the lowest value reported for 1.55 µm GaInAsP/InP quantum-wire lasers fabricated by the etching and regrowth method. Because of the temperature dependence of the lasing wavelength, a relatively large blue shift of 47 meV in the quantum-wire laser was observed, which can be attributed to not only a lateral quantum confinement effect but also a three-dimensional compressive strain effect. Finally, we improved the initial wafer structure in order to suppress over-etching of the active region, and obtained lasers consisting of a five-layered wirelike active region with good size uniformity (wire width of 42 nm, period of 120 nm). A threshold current density as low as 540 A/cm 2 was obtained with the cavity length of 1.38 mm.