GdInAsP/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 CH4/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 mu m. To our knowledge, this is the lowest value reported for 1.55 mu m GaInAsP/lnP 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.