Photo-induced Tellurium segregation in MoTe2
Abstract
We report on the coherent phonon spectroscopy of polymorphic MoTe2 single crystals using a femtosecond-pulsed laser to investigate the relationship between structural phase transitions and photo-thermal effects induced by high-density laser excitation. Even when a femtosecond pulsed laser was used, which generally induces fewer heat accumulation effects than the case for a CW laser, tellurium segregation was observed in coherent phonon spectra with increasing excitation density, while no structural phase transition among polymorphs of MoTe2 was observed. The use of higher photon-energy excitation, however, was found to suppress tellurium segregation.
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