Low-temperature, Inkjet-printed p-Type Copper(I) Iodide-based Thin-Film Transistors

by Jenna Y Gorecki

Institution: Oregon State University
Year: 2016
Keywords: Thin-Film Transistors; Thin film transistors
Posted: 02/05/2017
Record ID: 2124756
Full text PDF: http://hdl.handle.net/1957/59314


Inkjet-printed p-type copper(I) iodide-based TFTs were successfully fabricated. As-printed copper(I) halide semiconductor films, such as CuI, CuBrI, and CuClI, were used as p-type active channel layers for TFTs. The entire process of the TFTs fabrication was maintained under 150 °C, which is compatible with flexible plastic substrates and transparent glass substrate. Various printing temperatures, drop spacing, W/L ratios, and TFT structures were tested in order to find the optimum device properties for p-type copper(I) iodide-based TFT. In addition, inkjet-printed CuI, CuBrI, and CuClI films were characterized to study optical, electrical, and morphological properties. Furthermore, device performance of printed copper(I) iodide-based p-type TFTs was also investigated. Among them, CuI TFTs with SU-8 encapsulation exhibited outstanding p-type transistor behaviours with field-effect mobility as high as 4.36 cm² V⁻¹ s⁻¹ and Ion/Ioff ratio of 103.24 on the silicon substrate. Also, CuBrI TFTs resulted in successful p-type transistor behaviours with average field-effect mobility of 2.4 cm² V⁻¹ s⁻¹ and I[subscript on]/I[subscript off] ratio of 101.9 on the glass substrates when the molar ratio of CuBr:CuI was 1:1. In addition, CuClI TFTs were successfully fabricated with field-effect mobility as high as 1.02 cm² V⁻¹ s⁻¹ and I[subscript on]/I[subscript off] ratio of 10⁰·⁷³ on the silicon substrates when the molar ratio of CuCl:CuI was 1:9. The device performances were comparable to reported p-type metal oxide TFTs. This study suggests promising candidates of low-temperature printed p-type TFTs that can be used for complementary inorganic circuits. Advisors/Committee Members: Chang, Chih-hung (advisor), AuYeung, Nicholas (committee member).