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Updated: Jan 21, 2026

Seedless Growth of Bismuth Nanowire Array via Vacuum Thermal Evaporation
Published on: December 21, 2015
The Thermomechanical Properties of Thermally Evaporated Bismuth Triiodide Thin Films
Natália F Coutinho1, Silvia Cucatti2, Rafael B Merlo2
1"Gleb Wataghin" Institute of Physics - University of Campinas (UNICAMP), Campinas, SP, 13083-859, Brazil. nataliafcoutinho@gmail.com.
Abstract:
Bismuth triiodide (BiI3) has been studied in recent years with the aim of developing lead-free semiconductors for photovoltaics. It has also appeared in X-ray detectors due to the high density of the Bismuth element. This material is attractive as an active layer in solar cells, or may be feasible for conversion into perovskite-like material (MA3Bi2I9), being also suitable for photovoltaic applications. In this study, we report on the thermomechanical properties (stress, hardness, coefficient of thermal expansion, and biaxial and reduced Young's moduli) of BiI3 thin films deposited by thermal evaporation. The stress was determined as a function of temperature, adopting the thermally induced bending technique, which allowed us to extract the coefficient of thermal expansion (31 × 10-6 °C-1) and Young's biaxial modulus (19.6 GPa) for the films. Nanohardness (~0.76 GPa) and a reduced Young's modulus of 27.1 GPa were determined through nanoindentation measurements.
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