The five-layer Laminated Structure Organic Transistor Sensor Preparation and Characteristics Analysis

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1 , pp The five-layer Laminated Structure Organic Transistor Sensor Preparation and Characteristics Analysis Wei Liu, Dong-xing Wang, Bin An, Lei Wang, Jing-hua Yin, Hong Zhao College of Applied Science, Key Laboratory of Engineering Dielectrics and Its Application, Ministry of Education, Harbin University of Science and Technology, Harbin , China College of Applied Science, Electronic Science and Technology Harbin, China Abstract. In electronic devices field, there has been considerable interest in the study of organic substances such as phthalocyanines in thin film form for use as the active layer in gas sensor devices. In this paper, the device is simple manufacturing process, lower costs, and shows good Schottky characteristics. We use the vacuum deposition method and the organic semiconductor copper phthalocyanine or an organic gas-sensitive film make of the structure of Au (Emitte) / CuPc (organic gas sensors material) / Al (Base) / CuPc / Au (Collector) five-layer laminated structure organic transistor sensor. Tunneling CuPc / Al / CuPc Schottky Barrier barriers gate region formed due to the increase or decrease of the source emitter carriers, the working current is changed. Determination of the specific gas can be achieved by measuring the current change of the organic transistor sensor. It is successful implementation of the determination of NO 2 gas, and gas sensing sensitivity approximately 2.8. Keywords: laminated structure; copper phthalocyanine; an organic transistor sensor; the Schottky barrie. 1 Introduction NO2 is toxic gas in the atmosphere, and It is harmful to human health. To detect and protect the environment, it is important to measure the concentration of NO2 in the environment timely and accurately. we use the CuPc as the organic semiconductor gas sensitive materials, and design vertical organic thin-film transistor that its structure is consist of Au/CuPc/Al/CuPc/Au. The preparation process is using vacuum evaporation and sputtering by OLED coating system. When the specific gas NO 2 is absorbed on the organic film of organic thin-film transistor, take oxidation reaction equivalent to acceptor doping effect, make the changes of carriers in the organic film, inject the half-conductive Al-base, change the height of schottky barrier, and then drive the organic thin-film transistor. Working current which is producd by the current acrossing double schottky barrier would have a change because of the quantity of carriers that come from the emitter. ISSN: ASTL Copyright 2013 SERSC

2 We studied the organic transistor sensor, which uses the advantage of organic tunneling transistor current gain, and use the typical organic semiconductor materialᅳ copper phthalocyanine [9] (copper phthalocyanine: CuPc), specially appointed gases such as O 2, NO 2 will occur oxidation-reduction reduction when they were absorbed by the emitting region s organic thin film of organic transistor sensors, which equals to the doping effect of donor or acceptor, caused the change of carrier in organic film. To increase or decrease the carrier emitted by the collector, the tunneling CuPc / Al / CuPc double Schottky Barrier [10] base region is formed operating current and changed. According to measuring the current change of organic transistor sensor to determined a specific gas. With structure Au (Emitte) / CuPc / Al (Base) / CuPc / Au (Collector) a laminated structure of the organic transistor sensor (Vertical Type current Channel of quasi-conductor Al base Organic Semiconductor Copper Phthalocyanine Photovoltaic Thin Film Transistor; VOPTFT). 2 Laminated Structure of Organic Transistors Preparation Figure 1 is a configuration diagram of the sensor of an organic transistor, the structure of the glass substrate / Au (collector) / CuPc / Al (base) / CuPc / the Au (emitte). Solid phthalocyanine film adsorption of O2, the chemical reaction of MPC with O2 promote electronic mobile, O2 has played a role of electron capture trap: MPc, O 2 + e - MPc, O 2 - Phthalocyanine crystal adsorption NO2 gas conductance will change a lot, have higher gas conductance sensitivity, to the introduction of functional groups modified phthalocyanine-based material, such as lanthanide metal complexes dual-core phthalocyanine, rare earth metal sandwich structure ligand phthalocyanine, 16 fluorosubstituted zinc phthalocyanine [2] also has good gas sensing properties. This organic transistor sensor having a laminated structure take advantage of the high current gain VOTFT reduction reaction, when the organic thin film of the emitting region of the adsorption occurs simultaneously oxidized, Equivalent to the donor or acceptor role, 475 Copyright 2013 SERSC

3 resulting in the change of the organic film carrier. Determination of the specific gas can be achieved by measuring the current change of the organic transistor sensor.. 3 Organic Thin-film Transistor Sensor Test and Energy Band Changing Analysis Au / CuPc (130) / Al (20) / CuPc (70) / Au five layers the organic transistor sensor test results when placed in NO2 gas environment. I DS /ua air 7min 14min 21min 28min V DS /V Figure 2 is an organic transistor sensor placed in gas concentration 10ppm NO2 0min-28min I-V response curve. In the air, when the source-drain voltage VDS = 3V, the gate voltage VG = 0 the, the current value IDS = μA; placed in the NO2 gas after 7 minutes, IDS = 12.36μA, the current magnified about 2.8 times; found that, as time increases, the current the increasing, when in NO2 gas placed 28 minutes after, the voltage VDS = 3V, the current value IDS = μA the current amplification factor of approximately The carrier concentration in CuPc film increased when device adsorbed some NO2, which lead to decline in some of the quasi-femi level. Compared with the device which is placed in air, the Schottky barrier of CuPc/Al decrease for 60meV. Copyright 2013 SERSC 476

4 4 Characteristics and Discussion Using the vacuum deposition method and the organic semiconductor copper phthalocyanine or an organic gas-sensitive film make of the structure of Au (Emitte) / CuPc / Al (Base) / CuPc / Au (Collector) five-layer laminate structure organic transistor sensor. It will drive organic tunneling transistor current substantial changed much when organic transistor absorbs oxidizing gas. Determination of the specific gas can be achieved by measuring the current change of the organic transistor sensor. References 1. H. Dong, C. Wang, W. Hu, High performance organic semiconductors for field-effect transistor, Chemical communication, vol. 46, pp , P. Mittal, B. Kumar, Y. S. Negi, B. K. Kaushik and R. K. Singh, Organic Thin Film Transistor Architecture, Parameters and their Applications, CSNT International Conferenceon, pp , Chen X, Mao S S, Titanium Dioxide Nano-materials: Synthesis, Properties, Properties, Modifications, and Applications, Chemical Reviews, vol. 107, pp , Marinov, O. Dept. of Electr. & Comput. Eng., McMaster Univ., Hamilton, Ont., Canada. Charge transport in organic and polymer thin-film transistors: recent issues, Circuits, Devices and Systems, IEE Proceedings, pp , 3 June Belay A.B. Florida Solar Energy Center, Cocoa, FL, USA Wei Zhou; Krueger, R.; Davis, K.; Hickman, N., Polymerization and tuning optical property of PCBM, Photovoltaic Specialists Conference (PVSC), th IEEE, pp , June Baccarelli, R. Dept. of Electron. & Inf. Eng., Univ. of Perugia, Perugia, Italy. Feasibility study of a fully organic, CNT based, harmonic RFID gas sensor, RFID-Technologies and Applications (RFID-TA), 2012 IEEE International Conference on, pp , 5-7 Nov Copyright 2013 SERSC

5 7. Deptt. of Electron. & Comm. Eng., Integral Univ., Lucknow, India Abbas, Z.; Gopal, B., Experimental use of electronic nose for analysis of volatile organic compound (VOC), Multimedia, Signal Processing and Communication Technologies, IMPACT '09. International, pp , March Sirringhaus,,,Henning, Low-temerature,solution-processed organic transisters for flexible electronics, Technologies Beyond 2020 (TTM), 2011 IEEE Technology Time Machine Symposium on, pp.1, Uttiya,S. Dept. of Phys., Mahidol Univ., Bangkok. Pratontep, S.; Bhanthumnavin, W.; Buntem, R.; Kerdcharoen, T., Volatile organic compound sensor arrays based on zinc phthalocyanine and zinc porphyrin thin films Nanoelectronics Conference, INEC nd IEEE International, pp , March Sigdel, J. Dept. of Electr. Eng., Univ. of Texas at Tyler, Tyler, TX, USA Pieper, R.; Wondmagegn, W.; Puttagunta, V.; Satyala, Nikhil, Quasi-static modeling of an organic Schottky diode with trapped charge, System Theory (SSST), 2010, pp , 7-9 March N. Yamamoto, S. Tonomura, and H. Tsubomura, Hydrogen sensitive Schottky barriers in metal-copper phthalocyanine junctions and their photovoltaic effect, J. Appl. Phys., vol. 52, pp , Copyright 2013 SERSC 478