Gas Source MBE Growth and Characterization of TlInGaAs/InP DH Structures for Temperature-independent Wavelength LD Application
Abstract : TlInGaAs/InP double-hetero (DH) structures were grown on (100) InP substrates by gas source MBE. The photoluminescence (PL) peak energy variation with temperature decreased with increasing Tl composition. For the DH with a Tl composition of 13%, the PL peak energy varied only slightly with temperature (-0.03 meV/K). This value corresponds to a wavelength variation of 0.04 nm/K and is much smaller than that of the lasing wavelength of InGaAsP/InP distributed feedback laser diodes (0.1 nm/K). TlInGaAs/InP light emitting diodes with 6% Tl composition were fabricated and the small temperature variation of the electroluminescence peak energy (-0.09 meV/K) was observed at the wavelength around 1.58 micrometers. The results are promising to realize the temperature-independent wavelength laser diodes, which are important in the wavelength division multiplexing (WDM) optical fiber communication systems.
Photoconductance measurement on TlInGaP grown by gas source MBE
Abstract TlInP, TlGaP and TlInGaP layers are grown by gas source MBE and the temperature-dependence of their band gap energy is characterized with the photoconductance measurement. This material system was recently proposed by us for 0.9 μm to over 10 μm optical devices as well as temperature-insensitive-wavelength laser diodes. Photoconductance measurements on TlInP and TlInGaP grown on InP substrates show that their band gap energies are narrower than that of InP and that the temperature variation of band gap energy is weaker than those of InP and InAs as expected. Furthermore, photoconductance measurements on TlGaP grown on GaAs substrates show the absorption in the 1.4 μm wavelength region as well as the small temperature variation of absorption edge (band gap energy) as expected.
Single‐mode molecular beam epitaxy grown PbEuSeTe/PbTe buried‐heterostructure diode lasers for CO2 high‐resolution spectroscopy
Buried‐heterostructure tunable PbEuSeTe/PbTe lasers were fabricated using a two‐stage molecular beam epitaxy growth procedure. Improvements in the processing technique yielded lasers that show performance characteristics significantly better than those reported previously. A continuous wave (cw) operating temperature of 203 K was realized, which is the highest cw operating temperature ever reported for lead‐chalcogenides diode lasers. This laser exhibited exceptionally low‐threshold currents of 1.4 mA at 90 K and 43 mA at 160 K with single‐mode operation for injection currents up to 30Ith and 0.18 mW power at 100 K. The usefulness of the laser, when operating cw at 200 K, was demonstrated by the ability to perform high‐resolution spectroscopy of a low‐pressure CO2 gas sample.