Flexible Pressure-Sensitive Contact Transistors Operating in the

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Flexible Pressure-Sensitive Contact Transistors Operating in Subthreshold Regime Sanghoon Baek, Geun Yeol Bae, Jimin Kwon, Kilwon Cho, and Sungjune Jung ACS Appl. Mater. Interfaces, Just Accepted Manuscript • DOI: 10.1021/acsami.9b09636 • Publication Date (Web): 02 Aug 2019 Downloaded from pubs.acs.org on August 3, 2019

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ACS Applied Materials & Interfaces

Flexible Pressure-Sensitive Contact Transistors Operating in Subthreshold Regime Sanghoon Baek1,‡, Geun Yeol Bae2,‡, Jimin Kwon1, Kilwon Cho2,*, Sungjune Jung1,2,*

1Department

of Creative IT Engineering, Pohang University of Science and Technology

(POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, Republic of Korea

2Department

of Chemical Engineering, Pohang University of Science and Technology

(POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, 37673, Republic of Korea

KEYWORDS. Organic field-effect transistors, Pressure sensor, Electronic skin, Active matrix, Contact resistance, Gated Schottky contact Subthreshold operation, Low power consumption.

ABSTRACT

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Organic thin film transistors (TFTs)-based pressure sensors have received huge attention for wearable electronic applications such as health monitoring and smart robotics. However, there still remains a challenge to achieve low power consumption and high sensitivity at the same time for the realization of truly wearable sensor systems where minimizing power consumption is significant due to limited battery run time. Here, we introduce a flexible pressure-sensitive contact transistor (PCT), a new type of pressuresensing device based on an organic TFTs for next-generation wearable electronic skin devices. The PCT consists of deformable S/D electrodes integrated on a staggered TFT. The deformable S/D electrodes were fabricated by embedding conducting single-walled carbon nanotubes on surface of microstructured polydimethylsiloxane. Under pressure loads, the deformation of the electrodes on an organic semiconductor layer leads modulation of drain current from variation in both the channel geometry and contact resistance. By strategic subthreshold operation to minimize power consumption and increase the dominance of contact resistance due to gated Schottky contact, the PCT achieves both ultralow power consumption (order of 101 nW) and high sensitivity (18.96 kPa-1). Finally, we demonstrate a 5×5 active matrix PCT array on a 3-micron-thick


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Parylene substrate. The device with ultralow power consumption and high sensitivity on a biocompatible flexible substrate make the PCT promising candidate for next-generation wearable electronic skin devices.


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INTRODUCTION

Organic thin film transistors (TFTs) have enabled development of numerous flexible products, including flexible displays, ultrathin circuits, and wearable sensors.1–3 Their transformational advantages such as flexibility, light weight, thinness, and biocompatibility have extended their potential to various wearable sensor applications, such as biological and chemical sensors,4 and physical sensors.5 Among them, organic TFTbased pressure sensors that mimic the tactile sensing of human skin are promising candidates for wearable electronic skin (E-skin) technologies that include humanmachine interfaces, health monitoring devices, and advanced prosthesis.6–8 For skin-like devices that sense spatial pressure, organic TFTs can be fabricated into an array of sensor pixels addressed by an active matrix, and can exhibit superior electrical characteristics such as fast read-out, high spatial contrast, and minimal signal crosstalk.9

For the realization of truly wearable devices where minimizing power consumption is significant due to limited battery run time, organic TFT-based E-skins that consist of an array of multiple sensor pixels must have high sensitivity but consume minimal power.


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Various types of organic TFT-based pressure sensors have been investigated by the modulation of different parameters of organic TFTs.10–14 One representative approach modulates the effective electric field by exploiting a change of resistance typically from pressure sensitive rubber, PSR, connected to source (S) or drain (D) electrodes of individual organic TFT (one-transistor-one-resister structure).10,11,15–20 Another approach integrates a ferroelectric material (typically poly(vinylidene fluoride trifluoroethylene), P(VDF-TrFE)) into an individual organic TFT as a ferroelectric capacitor;14,21 however, their pressure sensitivity is limited by the properties of the integrated PSR and of the ferroelectric material. Another approach modulates the effective gate capacitance by incorporating a deformable dielectric layer such as microstructured elastomer (typically polydimethylsiloxane, PDMS) or air gap; this design achieves high sensitivity,12,13,22,23 but consumes much power for practical applications due to the height of the microstructures or a spacer for air gap which equals the dielectric thickness (typically >10 μm). High operating voltage in the range of 20 – 100V and power are necessary to demonstrate functioning systems. Several strategies to reduce operating power ( 5 kPa). Meanwhile, S in the above-threshold regime (VGS = -10 V) remained low (1.31 kPa-1) and began to saturate from 1 μm) deformable dielectric layers.12,13,22,23 Moving forwards, the key for ultralow power consumption without sacrificing sensitivity was strategical subthreshold operation followed by the careful consideration of the device physics occurring in subthreshold regime of organic TFTs, rather than just lowering the operating voltage. Therefore, the PCT operating in subthreshold regime has located at a highly desirable combination of ultralow power consumption (order of 101 nW) and high sensitivity (18.96 kPa-1) in a comparative plot of sensitivity versus power consumption of previously reported organic TFT-based E skins (Figure 6, Table S1).12,13,26,42–44,14,18,19,21–25 The static power consumption (Pstatic = ID∙VD ) was calculated from the maximum ID in pressure sensing range and VD of the device found in the literatures. The achieved sensitivity is the current record high for ultralow power (down to order of 101 nW) organic TFT-based E-skins. We envision that the subthreshold operating flexible contact transistor opens up new possibilities for wearable or skin-attachable electronic application where low-power and high-sensitivity are essential requirements.


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CONCLUSION

In conclusion, we introduced a flexible pressure-sensitive contact transistor (PCT), a new type of pressure-sensing device for the realization of truly wearable devices where low power consumption is vital. The deformable S/D electrodes fabricated by embedding conducting carbon nanotubes on surface of microstructured polydimethylsiloxane were integrated on a staggered TFT to provide pressure sensitivity to the device. The deformation of the electrodes on an organic semiconducting layer modulates the channel geometry and contact resistance, resulting in pressure-dependent ID. By strategic subthreshold operation where contact resistance is predominant due to gated Schottky contact, we achieved both ultralow power consumption (order of 101 nW) and high sensitivity (18.96 kPa-1). Finally, we demonstrated a 5×5 active matrix PCT array on a 3micron-thick Parylene substrate. Our PCT suggests the importance of contact behaviors in device physics of many organic TFT-based devices, and provides a path for achieving ultralow power consumption with high sensitivity simultaneously for the realization of wearable electronic devices.


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EXPERIMENTAL SECTION

Fabrication of the staggered organic TFT: PCTs were fabricated on biocompatible flexible Parylene C substrate. A Parylene (diX C, KISCO Ltd.) layer (≈ 3 μm) was deposited by chemical vapor deposition (CVD, OBANG TECHNOLOGY, OBT-PC300) on a surfactant-treated glass substrate (Corning) to be peeled off afterwards. Ti (3 nm)/ Al (50 nm) word lines and ground lines were thermally evaporated using a shadow mask of 5 × 5 active matrix with a pixel area of 3.92 mm2, and a total area of 2 cm × 2.5 cm. A dielectric layer (150 nm) of Parylene (diX C, KISCO Ltd.) was deposited by CVD. DPPDTT (M315, Ossila Inc.) dissolved in chlorobenzene (5 mg/ml) was then spin-coated at 3,000 rpm for 60 s and annealed at 100 °C for 30 min in a glovebox. Au (40 nm) contact pads for the deformable source/drain electrodes were thermally evaporated, and interconnection via-holes to connect source contact pads to the ground were formed using a pulsed green fiber laser (shot pulse width 2.5 ns, λ = 532 nm). Then the via-holes were filled by dispensing (Musashi Engineering, 350PC) Ag-precursor ink (TEC-IJ-060,


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InkTec) as a conductive metal ink and sintered at 100 °C for 30 min in an inert atmosphere.

Fabrication of the deformable S/D electrodes: For the fabrication of microstructured elastomer which served as deformable S/D electrodes, an Si mold patterned with pyramidal cavities was prepared by photolithography and wet etching processes.45 The surface was modified to be hydrophobic by treating with octadecyltrichlorosilane (Gelest), then the mold was spray-coated with SWNT-dispersed solution (Tuball, OCSiAl, SWNT conc. 0.3 g/L and sodium dodecylbenzenesulfonate (SDBS) conc. 0.3 wt% in deionized water (DIW)) by using an automated spray coater (ReVo-S, Korea). During coating, the temperature of the Si mold was 100 °C, the feed rate of the solution was 0.4 ml/mi, and the air pressure for atomizing was 0.3 MPa. To remove the SDBS, the mold was left in DIW at 60 °C for 1 h, then dried at 50 °C in a vacuum oven for 1 h. Then PDMS mixture (Sylgard 184, mixing ratio 10:1) was spin-coated on the SWNT-coated mold. The assembly was pressed using Parylene C-coated glass at a loading of 40 kPa for 30 min, then the PDMS was thermally cured at 60 °C for 8 h, then the SWNT-embedded


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microstructures with Parylene C substrate on glass were separated from the Si mold. The fabricated SWNT-embedded microstructure was then patterned to interdigitated source/drain electrodes by pulsed fiber laser with a pulse width of 2.5 ns and λ = 532 nm to serve as deformable electrodes (Drain electrodes were connected as bit lines). The channel length was 90 μm, and the channel width was 8280 μm. The fabricated deformable electrodes were integrated on the BGTC transistor array to complete the active matrix of the pressure-sensitive contact transistor.

Electrical characterization: Scanning electron microscopy (SEM) images were captured by using a Hitachi S-4800 operating at a beam voltage of 3 kV. The DC characteristics of the transistors were measured using a semiconductor parameter analyzer (Keithley, 4200-SCS) under ambient conditions. The pressure-sensing capability of the PCT was measured using a mechanized z-axis stage (Future Science, 0.1-µm resolution) and a force gauge (Mark 10, M7-05). The pressure was calculated by dividing the force by the size of the sensor (2.25 cm2). ID was measured in real time while applying constant VGS and VDS at various pressures. Spatial mapping of 5 × 5 active matrix was plotted by


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measuring the drain current of each cell before and after applying the pressure and calculating the ΔI/I0.


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FIGURES.

Figure 1. (a) 3D schematic diagram of the PCT consisting of deformable S/D electrodes integrated on the top of staggered organic TFT (without S/D electrodes). (b) SEM image of a pyramidal PDMS microstructure array with embedded single-walled carbon nanotubes. Width = 30 μm and interval = 60 μm (Scale bar = 30 μm (left) and 100 μm (right)). (c) SEM image of laser-patterned interdigitated S/D electrodes (deformable S/D electrodes). Channel length, L = 90 μm, and width W = 8280 μm (Scale bar = 200 μm). (d) Microscopic image (top view) of deformable S/D electrodes integrated on the gated area of the staggered organic TFT (Scale bar = 500 μm).


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Figure 2. (a) Side/projected-view schematic diagram of the PCT showing parameter changes upon pressure loading. (b) Microscopic images of contact area between deformable S/D electrodes and semiconductor under applied pressure (Scale bar = 10 μm). (c) Contact length d and corresponding channel geometrical parameter k = W/L change with applied pressure; bars: ± 1 s.d., n = 3.


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Figure 3. (a) Transfer characteristics with various applied pressures (0, 1.9, 10.3, and 38.7 kPa) where the threshold voltage at 0 kPa, VTH0 = -1.55 V. Drain voltage, VDS = -10 V. (black: abovethreshold regime (Above-T), red: subthreshold regime (Sub-T)). (b) Relative current change (ΔI/I0) with gate voltage (VGS) under various applied pressures (1.9, 10.3, and 38.7 kPa) where the maximum ΔI/I0 appears in Sub-T (VGS = -1.2 V). (c) ΔI/I0 as a function of applied pressure at different VGS (tangential slope: pressure sensitivity S). Bars: ± 1 s.d., n = 3.


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Figure 4. (a) The ΔI/I0 as a function of the relative channel geometrical parameter change Δk/k0 in above-T and sub-T regimes. Blue dashed line: y = x. (b) Normalized relative current change (ΔI/I0)/(Δk/k0) as a function of Δd at two different regimes; Above-T and Sub-T. (c) A schematic diagram of the current crowding model of the conventional staggered organic TFTs and the conceptual diagram of the contact length (d = LOV) change upon pressure in the PCT. (d) Positive threshold voltage (VTH) shift with applied pressure due to the reduction of the contact resistance RC from the enlarged contact length (d = LOV). (e) The normalized changes in the drain current ID(1/L)/(ID(1/L1)) as a function of 1/L in above-T and sub-T regimes. VDS = -10 V. Bars: ± 1 s.d., n = 3.


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Figure 5. (a) Microscopic image of each pixel of the PCT array. WL: word line, and BL: bit line. (Scale bar = 1 mm). (b) Photograph of the array peeled off from a glass carrier. Total size: 25 mm × 20 mm, and thickness = 3 μm (Scale bar = 1 cm). (c) Photograph of the flexible PCT array on the back of the hand as a proof-of-concept of a wearable E-skin (Scale bar = 2 cm). (d) Photograph of letter ‘E’ (≈ 4 kPa) positioned over the 5 × 5 PCT array (Scale bar = 5 mm). (e) Corresponding contour pressure map of the letter ‘E’ in above-T and sub-T regimes.


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Figure 6. Sensitivity versus power consumption of the PCT compared to representative organic TFT-based E-skins.


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ASSOCIATED CONTENT

Supporting Information The following files are available free of charge.

Device characteristics of the staggered organic TFT; Microscopic images of the contact area; Output characteristics of the PCT; Electrical responses of the PCT; Hysteresis of the PCT; Design of the active matrix PCT array; and Summary of previously reported organic TFT-based E-skins (PDF)

AUTHOR INFORMATION

Corresponding Author *E-mail: [email protected], [email protected]

Author Contributions The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript. ‡These authors contributed equally.


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Notes The authors declare no competing financial interest.

ACKNOWLEDGMENT

This work was supported by a grant (Code No. 2015M3A6A5072945) from the Center for Advanced Soft Electronics under the Global Frontier Research Program of the Ministry of Science and ICT of South Korea, by the “IT Consilience Creative Program” (IITP-20192011-1-00783) supervised by IITP *Institute for Information & Communications Technology Promotion).

REFERENCES (1)

Sirringhaus, H. 25th Anniversary Article: Organic Field-Effect Transistors: The Path Beyond Amorphous Silicon. Adv. Mater. 2014, 26 (9), 1319–1335.


32

Page 33 of 44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(2)

Kwon, J.; Takeda, Y.; Shiwaku, R.; Tokito, S.; Cho, K.; Jung, S. ThreeDimensional Monolithic Integration in Flexible Printed Organic Transistors. Nat.

Commun. 2019, 10 (1), 54.

(3)

Kwon, J.; Takeda, Y.; Fukuda, K.; Cho, K.; Tokito, S.; Jung, S. ThreeDimensional, Inkjet-Printed Organic Transistors and Integrated Circuits with 100% Yield, High Uniformity, and Long-Term Stability. ACS Nano 2016, 10 (11), 10324– 10330.

(4)

Lin, P.; Yan, F. Organic Thin-Film Transistors for Chemical and Biological Sensing. Adv. Mater. 2012, 24 (1), 34–51.

(5)

Someya, T.; Dodabalapur, A.; Huang, J.; See, K. C.; Katz, H. E. Chemical and Physical Sensing by Organic Field-Effect Transistors and Related Devices. Adv.

Mater. 2010, 22 (34), 3799–3811.

(6)

Hammock, M. L.; Chortos, A.; Tee, B. C. K.; Tok, J. B. H.; Bao, Z. 25th Anniversary Article: The Evolution of Electronic Skin (E-Skin): A Brief History,


33


Page 34 of 44

Design Considerations, and Recent Progress. Adv. Mater. 2013, 25 (42), 5997– 6038.

(7)

Bae, G. Y.; Han, J. T.; Lee, G.; Lee, S.; Kim, S. W.; Park, S.; Kwon, J.; Jung, S.; Cho, K. Pressure/Temperature Sensing Bimodal Electronic Skin with Stimulus Discriminability and Linear Sensitivity. Adv. Mater. 2018, 30 (43), 1803388.

(8)

Bae, G. Y.; Pak, S. W.; Kim, D.; Lee, G.; Kim, D. H.; Chung, Y.; Cho, K. Linearly and Highly Pressure-Sensitive Electronic Skin Based on a Bioinspired Hierarchical Structural Array. Adv. Mater. 2016, 28 (26), 5300–5306.

(9)

Wang, S.; Xu, J.; Wang, W.; Wang, G.-J. N.; Rastak, R.; Molina-Lopez, F.; Chung, J. W.; Niu, S.; Feig, V. R.; Lopez,; J. Lei, T.; Kwon, S.; Kim, Y.; Foudeh, A.M.; Ehrlich, A.; Gasperini, A.; Yun, Y.; Murmann, B.; Tok, J.B.-H.; Bao, Z. Skin Electronics from Scalable Fabrication of an Intrinsically Stretchable Transistor Array. Nature 2018, 555 (7694), 83–88.


34

Page 35 of 44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(10) Someya, T.; Sekitani, T.; Iba, S.; Kato, Y.; Kawaguchi, H.; Sakurai, T. A LargeArea, Flexible Pressure Sensor Matrix with Organic Field-Effect Transistors for Artificial Skin Applications. Proc. Natl. Acad. Sci. U. S. A. 2004, 101 (27), 9966– 9970.

(11) Takei, K.; Takahashi, T.; Ho, J. C.; Ko, H.; Gillies, A. G.; Leu, P. W.; Fearing, R. S.; Javey, A. Nanowire Active-Matrix Circuitry for Low-Voltage Macroscale Artificial Skin. Nat. Mater. 2010, 9 (10), 821–826.

(12) Schwartz, G.; Tee, B. C.-K.; Mei, J.; Appleton, A. L.; Kim, D. H.; Wang, H.; Bao, Z. Flexible Polymer Transistors with High Pressure Sensitivity for Application in Electronic Skin and Health Monitoring. Nat. Commun. 2013, 4 (1), 1859.

(13) Zang, Y.; Zhang, F.; Huang, D.; Gao, X.; Di, C.-A.; Zhu, D. Flexible Suspended Gate Organic Thin-Film Transistors for Ultra-Sensitive Pressure Detection. Nat.

Commun. 2015, 6, 6269.


35


Page 36 of 44

(14) Viola, F. A.; Spanu, A.; Ricci, P. C.; Bonfiglio, A.; Cosseddu, P. Ultrathin, Flexible and Multimodal Tactile Sensors Based on Organic Field-Effect Transistors. Sci.

Rep. 2018, 8 (1), 1–8.

(15) Someya, T.; Kato, Y.; Sekitani, T.; Iba, S.; Noguchi, Y.; Murase, Y.; Kawaguchi, H.; Sakurai, T. Conformable, Flexible, Large-Area Networks of Pressure and Thermal Sensors with Organic Transistor Active Matrixes. Proc. Natl. Acad. Sci. 2005, 102 (35), 12321–12325.

(16) Takahashi, T.; Takei, K.; Gillies, A. G.; Fearing, R. S.; Javey, A. Carbon Nanotube Active-Matrix Backplanes for Conformal Electronics and Sensors. Nano Lett. 2011, 11 (12), 5408–5413.

(17) Wang, C.; Hwang, D.; Yu, Z.; Takei, K.; Park, J.; Chen, T.; Ma, B.; Javey, A. UserInteractive Electronic Skin for Instantaneous Pressure Visualization. Nat. Mater. 2013, 12 (10), 899–904.


36

Page 37 of 44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(18) Sun, Q.; Kim, D. H.; Park, S. S.; Lee, N. Y.; Zhang, Y.; Lee, J. H.; Cho, K.; Cho, J. H. Transparent, Low-Power Pressure Sensor Matrix Based on Coplanar-Gate Graphene Transistors. Adv. Mater. 2014, 26 (27), 4735–4740.

(19) Yeom, C.; Chen, K.; Kiriya, D.; Yu, Z.; Cho, G.; Javey, A. Large-Area Compliant Tactile Sensors Using Printed Carbon Nanotube Active-Matrix Backplanes. Adv.

Mater. 2015, 27 (9), 1561–1566.

(20) Lee, S.; Reuveny, A.; Reeder, J.; Lee, S.; Jin, H.; Liu, Q.; Yokota, T.; Sekitani, T.; Isoyama, T.; Abe, Y.; Suo, Z.; Someya, T. A Transparent Bending-Insensitive Pressure Sensor. Nat. Nanotechnol. 2016, 11 (5), 472–478.

(21) Hannah, S.; Davidson, A.; Glesk, I.; Uttamchandani, D.; Dahiya, R.; Gleskova, H. Multifunctional Sensor Based on Organic Field-Effect Transistor and Ferroelectric Poly(Vinylidene Fluoride Trifluoroethylene). Org. Electron. physics, Mater. Appl. 2018, 56 (January), 170–177.


37


Page 38 of 44

(22) Mannsfeld, S. C. B.; Tee, B. C.-K.; Stoltenberg, R. M.; Chen, C. V. H.-H.; Barman, S.; Muir, B. V. O.; Sokolov, A. N.; Reese, C.; Bao, Z. Highly Sensitive Flexible Pressure Sensors with Microstructured Rubber Dielectric Layers. Nat. Mater. 2010, 9 (10), 859–864.

(23) Shin, S.; Ji, S.; Choi, S.; Pyo, K.; Wan An, B.; Park, J.; Kim, J.; Kim, J.; Lee, K.; Kwon, S.; Heo, J.; Park, B.; Park, J. Integrated Arrays of Air-Dielectric Graphene Transistors as Transparent Active-Matrix Pressure Sensors for Wide Pressure Ranges. Nat. Commun. 2017, 8, 14950.

(24) Kim, D.-I.; Quang Trung, T.; Hwang, B.-U.; Kim, J.-S.; Jeon, S.; Bae, J.; Park, J.J.; Lee, N.-E. A Sensor Array Using Multi-Functional Field-Effect Transistors with Ultrahigh Sensitivity and Precision for Bio-Monitoring. Sci. Rep. 2015, 5 (1), 12705.

(25) Hassinen, T.; Eiroma, K.; Mäkelä, T.; Ermolov, V. Printed Pressure Sensor Matrix with Organic Field-Effect Transistors. Sensors Actuators A Phys. 2015, 236, 343– 348.


38

Page 39 of 44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(26) Tsuji, Y.; Sakai, H.; Feng, L.; Guo, X.; Murata, H. Dual-Gate Low-Voltage Organic Transistor for Pressure Sensing. Appl. Phys. Express 2017, 10 (2), 021601.

(27) Liu, Z.; Yin, Z.; Wang, J.; Zheng, Q. Polyelectrolyte Dielectrics for Flexible LowVoltage Organic Thin-Film Transistors in Highly Sensitive Pressure Sensing. Adv.

Funct. Mater. 2019, 29 (1), 1806092.

(28) Xu, Y.; Sun, H.; Noh, Y. Schottky Barrier in Organic Transistors. IEEE Trans.

Electron Devices 2017, 64 (5), 1932–1943.

(29) Lee, S.; Nathan, A. Subthreshold Schottky-Barrier Thin-Film Transistors with Ultralow Power and High Intrinsic Gain. Science (80-. ). 2016, 354 (6310), 302– 304.

(30) Jiang, C.; Choi, H. W.; Cheng, X.; Ma, H.; Hasko, D.; Nathan, A. Printed Subthreshold Organic Transistors Operating at High Gain and Ultralow Power.

Science (80-. ). 2019, 363 (6428), 719–723.


39


Page 40 of 44

(31) Gao, X. P. A.; Zheng, G.; Lieber, C. M. Subthreshold Regime Has the Optimal Sensitivity for Nanowire FET Biosensors. Nano Lett. 2010, 10 (2), 547–552.

(32) Venkatraman, V.; Friedlein, J. T.; Giovannitti, A.; Maria, I. P.; McCulloch, I.; McLeod, R. R.; Rivnay, J. Subthreshold Operation of Organic Electrochemical Transistors for Biosignal Amplification. Adv. Sci. 2018, 1800453, 1800453.

(33) Marszalek, T.; Gazicki-Lipman, M.; Ulanski, J. Parylene C as a Versatile Dielectric Material for Organic Field-Effect Transistors. Beilstein J. Nanotechnol. 2017, 8 (1), 1532–1545.

(34) Li, J.; Zhao, Y.; Tan, H. S.; Guo, Y.; Di, C. A.; Yu, G.; Liu, Y.; Lin, M.; Lim, S. H.; Zhou, Y.; Su, H.; Ong, B. S. A Stable Solution-Processed Polymer Semiconductor with Record High-Mobility for Printed Transistors. Sci. Rep. 2012, 2, 1–9.

(35) Richards, T. J.; Sirringhaus, H. Analysis of the Contact Resistance in Staggered, Top-Gate Organic Field-Effect Transistors. J. Appl. Phys. 2007, 102 (9), 094510.


40

Page 41 of 44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(36) Wang, S. D.; Yan, Y.; Tsukagoshi, K. Understanding Contact Behavior in Organic Thin Film Transistors. Appl. Phys. Lett. 2010, 97 (6), 063307.

(37) Natali, D.; Chen, J.; Maddalena, F.; García Ferré, F.; Di Fonzo, F.; Caironi, M. Injection Length in Staggered Organic Thin Film Transistors: Assessment and Implications for Device Downscaling. Adv. Electron. Mater. 2016, 2 (8), 1600097.

(38) Park, J.; Do, L. M.; Pearson, C.; Petty, M.; Kim, D. W.; Choi, J. S. An Experimental Study of the Effects of Source/Drain to Gate Overlap in Pentacene Thin-Film Transistors. Jpn. J. Appl. Phys. 2012, 51 (9 PART3).

(39) Bittle, E. G.; Basham, J. I.; Jackson, T. N.; Jurchescu, O. D.; Gundlach, D. J. Mobility Overestimation Due to Gated Contacts in Organic Field-Effect Transistors. Nat. Commun. 2016, 7, 10908.

(40) Liu, C.; Li, G.; Di Pietro, R.; Huang, J.; Noh, Y.-Y.; Liu, X.; Minari, T. Device Physics of Contact Issues for the Overestimation and Underestimation of Carrier Mobility in Field-Effect Transistors. Phys. Rev. Appl. 2017, 8 (3), 034020.


41


Page 42 of 44

(41) Dargahi, J.; Najarian, S. Human Tactile Perception as a Standard for Artificial Tactile Sensing--a Review. Int. J. Med. Robot. 2004, 1 (1), 23–35.

(42) Kim, J.; Nga Ng, T.; Soo Kim, W. Highly Sensitive Tactile Sensors Integrated with Organic Transistors. Appl. Phys. Lett. 2012, 101 (10), 103308.

(43) Yeo, S. Y.; Park, S.; Yi, Y. J.; Kim, D. H.; Lim, J. A. Highly Sensitive Flexible Pressure Sensors Based on Printed Organic Transistors with Centro-Apically Self-Organized Organic Semiconductor Microstructures. ACS Appl. Mater.

Interfaces 2017, 9 (49), 42996–43003.

(44) Yin, Z.; Yin, M.; Liu, Z.; Zhang, Y.; Zhang, A. P.; Zheng, Q. Solution-Processed Bilayer Dielectrics for Flexible Low-Voltage Organic Field-Effect Transistors in Pressure-Sensing Applications. Adv. Sci. 2018, 5 (9), 1701041.

(45) Barycka, I.; Zubel, I. Silicon Anisotropic Etching in KOH-Isopropanol Etchant.

Sensors Actuators A Phys. 1995, 48 (3), 229–238.


42

Page 43 of 44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(46) Noguchi, Y.; Sekitani, T.; Someya, T. Organic-Transistor-Based Flexible Pressure Sensors Using Ink-Jet-Printed Electrodes and Gate Dielectric Layers. Appl. Phys.

Lett. 2006, 89 (25), 253507.

(47) Nela, L.; Tang, J.; Cao, Q.; Tulevski, G.; Han, S.-J. Large-Area High-Performance Flexible Pressure Sensor with Carbon Nanotube Active Matrix for Electronic Skin.

Nano Lett. 2018, 18 (3), 2054–2059.

(48) Kaltenbrunner, M.; Sekitani, T.; Reeder, J.; Yokota, T.; Kuribara, K.; Tokuhara, T.; Drack, M.; Schwödiauer, R.; Graz, I.; Bauer-Gogonea, S.; Bauer, S.; Someya, T. An Ultra-Lightweight Design for Imperceptible Plastic Electronics. Nature 2013,

499 (7459), 458–463.

(49) Yang, Z. W.; Pang, Y.; Zhang, L.; Lu, C.; Chen, J.; Zhou, T.; Zhang, C.; Wang, Z. L. Tribotronic Transistor Array as an Active Tactile Sensing System. ACS Nano 2016, 10 (12), 10912–10920.


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TABLE OF CONTENTS (TOC) GRAPHIC


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Flexible Pressure-Sensitive Contact Transistors Operating in the

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