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Raman investigation of the air stability of 2H polytype HfSe2 thin films

  • Antonio Cruz (a1), Zafer Mutlu (a2), Mihrimah Ozkan (a3) and Cengiz S. Ozkan (a1) (a4)


Hafnium diselenide (HfSe2) has a high theoretical carrier mobility but is among the most reactive transition-metal dichalcogenides (TMDs). Herein, we have investigated the air stability of 2H polytype HfSe2 single-crystal thin films by spectroscopic and microscopic techniques. Raman spectroscopy measurements in conjunction with atomic force microscopy reveal the formation of selenium-rich blisters on the surface of the crystals upon air exposure. Transmission electron microscopy analysis indicates that 2H-HfSe2 undergoes a spontaneous phase change to 1T-HfSe2. These results offer Raman spectroscopy as a fast, convenient, non-destructive technique to reliably monitor the surface degradation of TMDs and present an opportunity for further study of phase changes in this material.


Corresponding author

Address all correspondence to Cengiz S. Ozkan at


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Work performed during postdoctoral studies at the University of California, Riverside.



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Raman investigation of the air stability of 2H polytype HfSe2 thin films

  • Antonio Cruz (a1), Zafer Mutlu (a2), Mihrimah Ozkan (a3) and Cengiz S. Ozkan (a1) (a4)


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