Low-Temperature Sintering of In-Plane Self-Assembled ZnO Nanorods for Solution-Processed High-Performance Thin Film Transistors

High Resolution Image Download MS PowerPoint Slide ZnO is an attractive active semiconducting material for thin-film transistor (TFT) applications due to its high band gap, high mobility, ease of forming Ohmic contacts, and low toxicity. Here we present a process for solution fabrication of ZnO TFTs based on a simple, double-layer spin-coating process during which a dense layer of in-plane zinc oxide nanorods is deposited first, followed by coating of a chemical precursor solution and low-temperature annealing. First, a lower ZnO nanorod concentration can lead to the self-assembly of nanorods along the in-plane direction to form a relatively dense semiconductor layer. Then the chemical precursor solution sinters the nanorods and improves the contact between them. The n-channel TFTs exhibit high ON/OFF ratio of 10 5 −10 6, mobilities of ∼1.2 cm 2 V -1 s -1 and low threshold voltages of about −4 V with low hysteresis. We show that the quality of the semiconductor film and the minimum annealing temperature depends sensitively on the thickness and composition of the two layers.