High-performance organic–inorganic hybrid perovskite thin-film field-effect transistors

CH 3 NH 3 PbI 3 perovskite films with full coverage and negligible roughness have been obtained by the two-step sequential thermal evaporation (TSSTE) process, which are further applied to fabricate thin-film transistors (TFTs). To gain the optimal electrical characteristics in our TFTs, the effect of the evaporation amount of PbI 2 on the crystallization and thickness of CH 3 NH 3 PbI 3 films is studied during the process of TSSTE. As a result, we demonstrate a thin-film field-effect transistors possessing a hole field-effect mobility of 3.55 cm 2 V − 1 s − 1 as well as on/off ratio greater than 10 5 with the optimal CH 3 NH 3 PbI 3 films as the channel layer. Through a further comparative analysis, MoO 3 buffer layer is inserted between the perovskite channel layer and the source–drain electrode to improve the contact resistance of TFTs. As an understanding of device mechanism, a fact that insertion of MoO 3 buffer layer into the Au/perovskite interface significantly reduced the contact resistance from 705 to 0.2 kΩ cm is unveiled. By inserting MoO 3 buffer layer, the hole field-effect mobility of the CH 3 NH 3 PbI 3 organic–inorganic hybrid TFTs can reach to 7.47 cm 2 V − 1 s − 1 .