Keithley 4200 scs

The phase analysis of the prepared thin film was carried out by X-ray diffraction (XRD, Cu Kα radiation with λ = 1.5418 Å, Bruker D8 ADVANCE, Karlsruhe, Germany). The surface morphology of the prepared thin film was observed by a scanning electron microscope (SEM, TESCAN AMBER, Brno, Czech Republic) and atomic force microscope (AFM, Bruker Multimode8, Billerica, MA, USA). The cross-sectional image of prepared thin films was observed by a scanning electron microscope (SEM, Hitachi S3400, Tokyo, Japan). The memory current-voltage scanning was performed using a semiconductor parameter analyzer (Keithley 4200-SCS, Tektronix, Beaverton, OR, USA).

Crystal phase structures of the CaTiO₃ nanopowder and pentacene were characterized by an MiniFlex 600 X-ray diffraction (XRD) instrument (Rigagu, TKY, Japan) over the 2θ of 10°to 80°. Electrical characteristics (capacitance vs. voltage, current vs. voltage) of OFETs were performed by a Keithley 4200-SCS semiconductor parameter analyzer (Tektronix, Johnston, OHIO, USA), whereby all electrical measurements were carried out in air. The surface morphologies of the dielectric films and pentacene were characterized with an SPI 400 atomic force microscope (HITACHI, TKY, Japan) in tapping mode. The surface energies of insulators were established by measuring the contact angle using a Kino SL200 KS goniometer. Film thickness was tested by Tencor D-100 step profiler (KLA, Milpitas, CA, USA). During the interval of the bending test, the device is kept bent (50 mm) and placed in a glove box filled with nitrogen to avoid the influence of water and oxygen in the air on the pentacene.

A SiO₂ window (2 mm × 2 mm) was first defined on a SiO₂ (300 nm)/Si (n-type, resistivity of 1–10 Ω cm) wafer through a wet etching process. Then, the 1Tʹ-MoTe₂ layer was directly deposited on a pre-patterned SiO₂/Si wafer to construct a 1Tʹ-MoTe₂/Si Schottky junction device. Afterward, the Au (50 nm) and In-Ga alloy electrodes were defined on the MoTe₂ layer and the back side of the Si wafer, respectively. Then a monolayer graphene film on the top surface of MoTe₂ was chosen as the transparent electrode. The electrical and optoelectrical properties of the devices were investigated by a Keithley 4200-SCS (Tektronix), an oscilloscope (DPO2012B, Tektronix), and light sources with various wavelengths. The noise current of the device was measured by a semiconductor parameter analyzer system (Fs-pro, Primarius). Imaging measurements were performed with a lab-built imaging system. The hollow mask with “LWIR” patterns was mounted on a 2D motorized positioning system, programmed to move in a plane with each step of 0.5 mm. The device was located behind the mask. The position-dependent current of the device was detected by a lock-in amplifier when the mask moved.

The as-prepared film was investigated by scanning electron microscopy (SEM, Hitachi S4800, Tokyo, Japan), Energy Dispersive X-ray Fluorescence (EDX) analyses were performed using a Hatchi s-4800 field emission scanning electron microscope (Hitachi, Tokyo, Japan) UV–Vis absorption spectra lambda750 (PerkinElmer Inc, Shanghai, China), and Raman spectra HR 800 (HORIBA JobinYvon, JobinYvon, France). The electrical characteristics of device were investigated by Keithley 4200 SCS (Tektronix Inc., Beaverton, OR, USA). The device was placed on a probe station in a clean and shielded box. The 365-nm UV light source with adjustable power density was provided by UVEC-4 (Shen Zhen Lamplic Tech Co., Shenzhen, China). All measurements were performed in ambient conditions at room temperature.

Distances ranging from 20 to 220 mm were applied by using a probing station (Keithley 4200-SCS, Tektronix, USA). The TPU-CNT film was fixed over a glass substrate to eliminate noise and the sensing object (brass bar—10 mm (height) × 20 mm (width) × 200 mm (length)) started approaching the sample with a speed of 6.6 mm/s after 60 s (Video S1). The impedance analysis was performed by the modular instrumentation using a probing station. To detect the maximum change in the capacitance, the samples were pre-soaked with 5 V direct current (DC) to saturate and reduce the tunneling effect and also to polarize the polymer and form the surface charge. Furthermore, a 30 mv alternate current (AC) swiping signal was applied to measure the capacitance of the film with varying frequencies to achieve maximum stability of the working window for the fabricated sensors. As demonstrated in Fig. 1a,b, the experimental setup and how change of capacitance to the initial capacitance ( $\mathrm{\Delta }C/C_0)$ were analyzed. The sensor probes were mechanically co-planner with an angle of 45° to eliminate the noise and reduce the penetration depth inside the film. The entire three set of tests were done for each CNT content. Other conditions, including temperature and humidity, were strictly controlled to obtain a precise measurement.