Investigation of Rapid Low-Power Microwave-Induction Heating Scheme on the Cross-Linking Process of the Poly(4-vinylphenol) for the Gate Insulator of Pentacene-Based Thin-Film Transistors

Abstract

In this study, a proposed Microwave-Induction Heating (MIH) scheme has been systematically studied to acquire suitable MIH parameters including chamber pressure, microwave power and heating time. The proposed MIH means that the thin indium tin oxide (ITO) metal below the Poly(4-vinylphenol) (PVP) film is heated rapidly by microwave irradiation and the heated ITO metal gate can heat the PVP gate insulator, resulting in PVP cross-linking. It is found that the attenuation of the microwave energy decreases with the decreasing chamber pressure. The optimal conditions are a power of 50 W, a heating time of 5 min, and a chamber pressure of 20 mTorr. When suitable MIH parameters were used, the effect of PVP cross-linking and the device performance were similar to those obtained using traditional oven heating, even though the cross-linking time was significantly decreased from 1 h to 5 min. Besides the gate leakage current, the interface trap state density (Nit) was also calculated to describe the interface status between the gate insulator and the active layer. The lowest interface trap state density can be found in the device with the PVP gate insulator cross-linked by using the optimal MIH condition. Therefore, it is believed that the MIH scheme is a good candidate to cross-link the PVP gate insulator for organic thin-film transistor applications as a result of its features of rapid heating (5 min) and low-power microwave-irradiation (50 W).

Bias Stress in Organic Thin-Film Transistors Towards Low-Cost Flexible Gas Sensors

“…By taking into account that Nit ~ 7.8×10 12 eV -1 cm -2 on OTS-treated SiO2, the interface with PVP:PMF seems to suffer from deeper traps in energy with longer releasing time constants [48]. These values are comparable to previous untreated PVP-based transistors [34,[49][50][51]. Differences in performance after stress can be related to accentuated trapping from hydroxyl groups at the PVP backbone [31,38].…”

Sulpho-Salicylic Acid Grafted to Ferrite Nanoparticles for n-Type Organic Semiconductors

“…Similar-shaped transfer characteristics to other OTFTs with a p-type pentacene [ 23 ] or an n-type organic [ 24 ] film are also visible in Figure 7 a,b. We selected these two transistors [ 23 , 24 ] for comparison for a few reasons: (i) Pentacene is a reference material for organic transistors, such as Si for inorganic devices; (ii) pentacene usually presents p-type conduction [ 7 , 23 , 25 ], but under special conditions, pentacene offers n-type conduction [ 8 , 26 ]; (iii) we compared the transfer characteristics of our test OTFT with those of the p-type pentacene OTFT—obviously, the chosen I D -V GS points of p-type pentacene from [ 23 ] were inserted on the axis in Figure 7 , considering V GS = |V GS |; (iv) for further comparisons, we considered BASF material (BASF is a code of a perylene derivative used as an n-type film in [ 24 ]) in Figure 7 , because it is an n-type material and it is a more recent development.…”

“…This method works at room temperature and it is suitable for the deposition of 100 nm organic layers. Polymers with small molecules, such as pentacene, are the most widely used organic semiconductors for p-type materials nowadays [ 7 ], as well as for n-type materials under special conditions [ 8 ]. The precursors of pentacene are polycyclic aromatic hydrocarbons (PAHs), and their toxicity comes from the ability of these PAHs to bind to deoxyribonucleic acid inside cells, thereby producing disruptive effects [ 9 ].…”