Rapid growth of high-performance Bi2Te3 thin films by laser annealing at room temperature

Bismuth telluride, (Bi 2 Te 3 ), is of great scientific and technical importance due to its excellent thermoelectric performance near room temperature. However, deposition of Bi 2 Te 3 thin films suffers from composition deviation due to preferential loss of Te at a high-temperature deposition environment. We demonstrated a fast and efficient laser annealing method to synthesize high-quality stoichiometric Bi 2 Te 3 thin films at room temperature from Te/Bi stacking films. The production rate of Bi 2 Te 3 was around 180 times higher than conventional thermal annealing. The formation of Bi 2 Te 3 thin films was studied with respect to annealing laser energy density . Bi 2 Te 3 thin films with an Bi:Te atomic ratio of 2:3 were achieved at an annealing laser energy density of 6.6 mJ/cm 2 . The structural, chemical, and thermoelectric performance of laser-annealed films were compared with conventional thermally annealed films. The Seebeck coefficient of laser-annealed films reached −167 µV/K, which was1.3 higher than that of thermally annealed films, evidencing the superiority of the laser annealing method in producing high quality Bi 2 Te 3 stochiometric films. Rapid growth of stoichiometric Bi 2 Te 3 thin films by laser annealing holds great promise for the development of high-performance thermoelectric devices.