Direct growth of Bismuth Telluride nanowires by On-Film Formation of Nanowires for high-efficiency thermoelectric devices

We report a novel stress-induced method to grow single crystalline Bi2Te3 nanowires, On Film Formation of Nanowires (OFF-ON), their growth mechanism and transport properties. Single crystalline Bi2Te3 nanowires were found to grow on as-sputter ed BiTe films after thermal annealing at 350°C. This growth was facilitated by stress relaxation between the film and the thermally oxidized Si substrate originating from a mismatch of the thermal expansion. The mechanism for wire growth is stress-induced mass flow along grain boundaries in the polycrystalline film.