Ultrastable Amorphous Sb₂Se₃ Film

Increasing the thermostability of amorphous materials has been a long journey to improve their properties. The metastable nature of chalcogenide glasses limits their practical applications as an amorphous semiconductor in photovoltaic performance. Here, we report the formation and physical properties of ultrastable amorphous Sb₂Se₃ with an enhanced thermal stability compared to ordinary amorphous Sb₂Se₃ (ΔT_x= 17 K). By in situ high temperature-high energy synchrotron X-ray diffraction, the difference in structure relaxation between ordinary and ultrastable amorphous Sb₂Se₃ was manifested by local structure evolution. Ultrastable amorphous Sb₂Se₃ showed the smallest surface roughness and highest refractive index, the mechanism behind was further discussed in terms of fast molecular mobility and molecular orientation during vapor deposition. Formation of ultrastable amorphous Sb₂Se₃ demonstrated a promising avenue to obtain novel functional amorphous semiconductor with modulated structure and property.