Enhanced Electrical Performance and Stability of Solution-Processed Thin-Film Transistors with In(2)O(3)/In(2)O(3):Gd Heterojunction Channel Layer

The use of the semiconductor heterojunction channel layer has been explored as a method for improving the performance of metal oxide thin-film transistors (TFTs). The excellent electrical performance and stability of heterojunction TFTs is easy for vacuum-based techniques, but difficult for the solution process. Here, we fabricated In(2)O(3)/In(2)O(3):Gd (In(2)O(3)/InGdO) heterojunction TFTs using a solution process and compared the electrical properties with single-layer In(2)O(3) TFTs and In(2)O(3):Gd (InGdO) TFTs. The In(2)O(3)/InGdO TFT consisted of a highly conductive In(2)O(3) film as the primary transmission layer and a subconductive InGdO film as the buffer layer, and exhibited excellent electrical performance. Furthermore, by altering the Gd dopant concentration, we obtained an optimal In(2)O(3)/InGdO TFT with a higher saturation mobility (µ) of 4.34 cm(2)V(−1)s(−1), a near-zero threshold voltage (V(th)), a small off-state current (I(off)) of [Formula: see text] A, a large on/off current ratio (I(on)/I(off)) of [Formula: see text] , a small subthreshold swing (SS), and an appropriate positive bias stability (PBS). Finally, an aging test was performed after three months, indicating that In(2)O(3)/InGdO TFTs enable long-term air stability while retaining a high-mobility optimal switching property. This study suggests that the role of a high-performance In(2)O(3)/InGdO heterojunction channel layer fabricated by the solution process in the TFT is underlined, which further explores a broad pathway for the development of high-performance, low-cost, and large-area oxide electronics.