Tellurium Single-Crystal Arrays by Low-Temperature Evaporation and Crystallization

Thermally evaporated tellurium possesses an intriguing crystallization behavior, where an amorphous to crystalline phase transition happens at near-ambient temperature. However, a comprehensive understanding and delicate control of the crystallization process for the evaporated Te films is lacking. Here, the kinetics and dynamics of the crystallization of thermally evaporated Te films is visualized and modeled. Low-temperature processing of highly crystalline tellurium films with large grain size and preferred out-of-plane orientation ((100) plane parallel to the surface) is demonstrated by controlling the crystallization process. Tellurium single crystals with a lateral dimension of up to 6 µm are realized on various substrates including glass and plastic. Field-effect transistors based on 5 °C crystallized Te single grains (6-nm-thick) exhibit an average effective hole mobility of ≈100 cm² V⁻¹ s⁻¹, and on/off current ratio of ≈3 × 10⁴.