Multimode Operation of Organic–Inorganic Hybrid Thin-Film Transistors Based on Solution-Processed Indium Oxide Films

Abstract

Solution-processed metal oxide (MO) thin films have been extensively studied for use in thin-film transistors (TFTs) due to their high optical transparency, simplicity of fabrication methods, and high electron mobility. Here, we report, for the first time, the improvement of the electronic properties of solution-processed indium oxide (InO x ) films by the subsequent addition of an organic p-type semiconductor material, here 6,13bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene), yielding organic−inorganic hybrid TFTs. The addition of TIPS-pentacene not only improves the electron mobility by enhancing the charge carrier percolation pathways but also improves the electronic and temporal stability of the I DS (V G ) characteristics as well as reduces the number of required spin-coating steps of the InO x precursor solution. Very interestingly, the introduction of 10 nm TIPSpentacene films on top of 15 nm InO x layers allows the fabrication of either enhancement-or depletion-mode devices with only minimal changes to the fabrication process. Specifically, we find that when the TIPS-pentacene layer is added on top of the source/ drain electrodes, resulting in devices with embedded source/drain electrodes [embedded electrode TFTs (EETFTs)], the devices exhibit an enhancement-mode behavior with an average mobility (μ) of 6.4 cm 2 V −1 s −1 , a source−drain current ratio (I on /I off ) of around 10 5 , and a near-zero threshold voltage (V TH ). When on the other hand the TIPS-pentacene layer is added before the source− drain electrodes, i.e., in top-contact electrode TFTs (TCETFTs), a very clear depletion mode behavior is observed with an average μ of 6.3 cm 2 V −1 s −1 , an I on /I off ratio of over 10 5 , and a V TH of −80.3 V. Furthermore, a logic inverter is fabricated combining the enhancement (EETFTs)-and depletion (TCETFTs)-mode transistors, which shows a potential for the construction of organic− inorganic hybrid electronics and circuits.

Analysis of the Annealing Budget of Metal Oxide Thin‐Film Transistors Prepared by an Aqueous Blade‐Coating Process

“…The strong peak is located at 2.22 Å −1 corresponding to (222) plane of the cubic oxide phase in In 2 O 3 . [ 69 ] Additionally, the GIWAXS pattern of ZnO x films showed (100), (002), and (101) diffraction rings related to a regular wurtzite crystal of ZnO, indicating the successful synthesis of ZnO in the ZnO x films (Figure S5, Supporting Information). [ 70 ] With the extension of annealing time after 600 s, the crystallinity of the MO films did not improve significantly.…”