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

• Published in: Journal of physical chemistry. C 2007-12, Vol.111 (51), p.18831-18835
• Main Authors: Sun, Baoquan, Peterson, Rebecca L, Sirringhaus, Henning, Mori, Kiyotaka
• Format: Article
• Language: English
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp077740f

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 105−106, mobilities of ∼1.2 cm2 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.