Synthesis of ZnO Nanoparticles to Fabricate a Mask-Free Thin-Film Transistor by Inkjet Printing

Abstract

We report a low-cost, mask-free, reduced material wastage, deposited technology using transparent, directly printable, air-stable semiconductor slurries and dielectric solutions. We have demonstrate an emerging process for fabricating printable transistors with ZnO nanoparticles as the active channel and poly(4-vinylphenol) (PVP) matrix as the gate dielectric, respectively, and the inkjet-printed ZnO TFTs have shown to exhibit the carrier mobility of 0.69 cm2/Vs and the threshold voltage of 25.5 V. We suggest that the printable materials and the printing technology enable the use of all-printed low-cost flexible displays and other transparent electronic applications.

Inkjet Printed Thin Film Transistors Using Cadmium Sulfide as Active Layer Prepared by In-Situ Micro-Reaction

“…36 However, in CBD, large amounts of material are wasted and just a small percentage is deposited as functional films. 6 The low mobility observed in the films studied here is likely limited by the presence of defects in the film due to nanocrystallites grain boundaries that could act as scattering centers. 37 Therefore, further performance improvement can be achieved by increasing the grain size to minimize grain boundaries and reduce carrier scattering.…”

“…This annealing can also result in film cracking and peeling-off. 6 In this letter, we report an inexpensive and low material wastage additive method to grow CdS thin-films for active layer in TFTs. This is an easy and simple process that combines merits of in-situ synthesis where the reaction happens directly at the interface with the substrate (dielectric in this case).…”

“…Besides the inexpensive aspect of Inkjet printing, additional advantages include the ability to deposit a wide range of materials, as well as low material wastage. [1][2][3][4][5][6] Currently, most inkjetprinted semiconductors for flexible electronics are organic, which typically have poor performance with mobilities around 0.1-1 cm 2 /V · s. Stability is also a potential issue for organic materials since its poor air and moisture stability compromise device reliability. 7 On the other hand, inorganic materials, in particular chalcogenide nanoparticles, have attracted the attention because these materials can be solutionprocessed and are chemically stable upon exposure to air.…”

Optimization of Transistor Characteristics and Charge Transport in Solution Processed ZnO Thin Films Grown from Zinc Neodecanoate

“…Initially, majority of ZnO TFTs were primarily fabricated using vacuum based deposition techniques such as ion beam sputtering [27], RF magnetron sputtering [28,29], pulsed laser deposition [30] and atomic layer deposition [31]. However, more recently low cost solution based techniques such as spin coating [6,32], spray coating [5,33] and ink-jet printing [34,35] have also been explored to yield performance level comparable with vacuum based devices. Solution processed thin films of ZnO have been achieved either by utilizing a suspension of ZnO nanoparticles or by decomposition of Zn precursors [36].…”

Printing ZnO Inks: From Principles to Devices

“…Printed TFT devices based on inkjetted ZnO NPs have been reported in recent years. Liu et al [138] followed a low-cost, mask-free approach to fabricate bottom-gate, top-contact TFTs where both the gate dielectric and the active channel were ink-jet printed by using ZnO NP and poly(4-viylphenol) (PVP) polymer matrix-based inks, respectively. However, this device exhibited relatively poor performance, with a current on/off ratio of 4 × 10 1 , a carrier mobility of 0.69 cm 2 /Vs, and a threshold voltage of 25.5 V. Better results were achieved by Lim et al [139] who also reported on a bottom-gate n-channel ZnO TFT, where a ZnO suspension of nanorods was inkjet-printed to pattern the ZnO active channel.…”