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.
Gas source MBE growth of Tl-containing semiconductors and their application to temperature-insensitive wavelength laser diodes
TlInGaAs/InP system was proposed to fabricate the temperature-insensitive wavelength laser diodes (LDs), which are important in the WDM optical fiber communication system. They were grown by gas source MBE. It was confirmed that the temperature coefficient of the refractive index for TlInGaAs is reduced by the addition/increase of Tl composition in TlInGaAs at both below and above the direct band-gap E/sub 0/ edge. It was also confirmed that the temperature coefficient of the E/sub 0/ edge is reduced. Current injection pulsed laser operation was obtained up to 310 K. Threshold current density and lasing wavelength at room temperature were 7 kA/cm/sup 2/ and 1665 nm, respectively. We have observed the small temperature variation of the longitudinal-mode peak wavelength as small as 0.06 nm/K, which is smaller than that for the InGaAsP/InP DFB LDs.
Gas source molecular beam epitaxy growth of TlInP for new infrared optical devices
Gas source molecular beam epitaxy growth of TlInP (thallium indium phosphide) on (100) InP substrate is described. TlInP is an important constituent material of newly proposed novel infrared optical device material, TlInGaP, which can be lattice-matched to InP. Reflection high-energy electron diffraction reveals the (2×2), (2×4), and (4×2) streak patterns corresponding to the P-excess, P-stabilized and group-III rich surfaces, respectively. However, facet pattern emerges in the low temperature (380 °C) growth. This pattern is consistent with the scanning electron microscopy image; hatched pattern along the [011] direction, which is caused by insufficient migration of group III adatoms on the surface. Double crystal x-ray diffraction rocking curves for TlP on InP and TlInP on InP samples clearly show the peak from TlP and TlInP as well as that from InP substrate. The peak position is changed with Tl/In flux ratio. Photoluminescence emission is observed for TlInP grown on InP.