Field-effect transistors with vacuum-deposited organic-inorganic perovskite films as semiconductor channels

Films of the organic-inorganic layered perovskite (C₆H₅C₂H₄NH₃)₂SnI₄ were vacuum-deposited on substrates heated at various temperatures (T_sub) to investigate the influence of T_sub on their film quality and transistor performance (hole mobilities, threshold voltages, and current on/off ratios). Appropriate substrate heating at T_sub = 60 °C during vacuum deposition led to better-developed perovskite films with larger grains. These films exhibited the best transistor performance in comparison with films fabricated at the other T_sub. The transistor performance was further enhanced by reducing perovskite semiconductor thickness (t) because of a reduction of bulk resistance in a top-contact/bottom-gate transistor structure. By utilizing the optimized T_sub of 60 °C and t of 31 nm, we obtained the most improved hole mobility of 0.78 ± 0.24 cm²/V s, about 5000 times the hole mobilities of our initial transistors fabricated at T_sub = 24 °C and t = 50 nm.