Growth and structural characteristics of metastable β-In2Se3 thin films on H-terminated Si(111) substrates by molecular beam epitaxy*

Epitaxial growth and structural characteristics of metastable β -In 2 Se 3 thin films on H-terminated Si(111) substrates are studied. The In 2 Se 3 thin films grown below the β -to- α phase transition temperature (453 K) are characterized to be strained β -In 2 Se 3 mixed with significant γ -In 2 Se 3 phases. The pure-phased single-crystalline β -In 2 Se 3 can be reproducibly achieved by in situ annealing the as-deposited poly-crystalline In 2 Se 3 within the phase equilibrium temperature window of β -In 2 Se 3 . It is suggeted that the observed γ -to- β phase transition triggered by quite a low annealing temperature should be a rather lowered phase transition barrier of the epitaxy-stabilized In 2 Se 3 thin-film system at a state far from thermodynamic equilibrium.