Studying saturation mobility, threshold voltage, and stability of PMMA-SiO2-TMSPM nano-hybrid as OFET gate dielectric

- The PMMA-SiO2-TMSPM nano-hybrid samples were prepared using sol-gel technique.
- PMMA-SiO2-TMSPM thin films were fabricated by spin coating technique on p-type Si.
- Influence of surface morphology devices on the leakage current density, charge-carrier mobility and output current were studied.
- At VDS = -10 V, the OFET device exhibited good transfer characteristics such as μFET,S of 0.0749 cm2 s−1 V−1 and Vth of 32 V.
- By applying high voltages to the gate dielectric (VGS = -80 V), the OFET devices had good stability.

PMMA-SiO2-TMSPM (polymethyl methacrylate- silicon oxide- (3-trimethoxysilyl)propyl methacrylate) nano-hybrid solutions were synthesized using sol-gel process with the constant weight ratio of PMMA-SiO2 and different weight ratios of TMSPM. Hybrid solutions were deposited on p-type Si (111) substrate using the spin coating technique. Surface morphology was studied using scanning electron microscopy (SEM) technique and the size of the nanoparticles was about 6 nm to 13 nm. Capacitance-voltage (C-f) measurements and current-voltage (I-V) curves were also studied in metal-insulator-semiconductor (MIS) structures. According to the results presented from JGS curves in terms of VGS, the gate leakage current densities were small enough to be used as gate dielectric material in OFETs. At VDS = −10 V, in the saturation region, it is considered (transfer characteristic curves), maximum mobility μS,FET was related to the sample without TMSPM because of its minimum dielectric constant. However, the surface morphology of this sample shows discontinuous nanoparticles with maximum traps on the path, which led to decreased IDS in the channel. To overcome this challenge, other samples were produced in the presence of TMSPM as the coupling agent. The sample with 0.15 wt ratio of TMSPM has flatter surface morphology and more continuous dispersion than that of other samples so that the number of traps on the path decrease, nanoparticles distribute continuously on the surface of the thin films, and IDS increased in the channel. By applying high gate voltages (VGS = −80 V), according to IDS curves in terms of VDS, the OFETs show good stability.

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