Gas-source MBE growth of Tl-based III-V semiconductors and their Raman scattering characterization

Ternary TlGaP and TlGaAs alloys, which are important constituent quaternary alloys of TlxIn1 - x - yGayP and TlxIn1 - x- yGayAs as new III-V compound semiconductors for long wavelength optical devices as well as temperature-i nsensitive wavelength laser diodes, are successfully grown by gas-source mo lecular beam epitaxy (MBE). Optical phonon modes of TIGaP and TlGaAs ternar y alloys are investigated, for the first time, by Raman scattering measurem ent. The Raman spectra of TIGaP with larger Tl composition on GaAs substrat e consist of four separate bands in the optical frequency range, GaP-like L O 393 cm(-1), GaP-like TO 357 cm(-1), TlP-like LO 346 cm(-1) and TlP-like T O 307 cm(-1), respectively. The GaAs-like phonon modes for TlGaAs on InP su bstrate are also observed. The results show an agreement between the Raman scattering measurements and X-ray diffraction experiments. (C) 2000 Elsevie r Science B.V. All rights reserved.