Development of Flexible Photo Sensor and Memory Devices Based on Organic Photo FET
- PDF / 419,641 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 40 Downloads / 185 Views
0965-S10-09
Development of Flexible Photo Sensor and Memory Devices Based on Organic Photo FET Manabu Yoshida1, Hiroki Kawai2, Takeshi Kondoh2, Takeshi Kawai2, Kouji Suemori1, Sei Uemura1, Satoshi Hoshino1, Takehito Kodzasa1, and Toshihide Kamata1 1 Organic Semiconductor Device Group, National Institute of Advanced Industrial Science and Technology, Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8565, Japan 2 Faculty of Engineering, Tokyo University of Science, 1-3 Kagurazaka, Shinjyuku-ku, Tokyo, 162-8601, Japan
ABSTRACT The photo FET having a photosensitive insulator layer showed excellent photo-switching properties upon illuminating the gate dielectric layer, because the gate capacitor was rapidly charged up by providing a large amount of photo-generated charges in the dielectric layer to the gate capacitor. In this study, we have tried to give a memory function to the photo FET. Further, we have tried to fabricate flexible photo FETs by using only solution processes in order to utilize the photo FET as flexible photo sensor and photo memory devices. As a result, we have succeeded in observing the memory effect of the photo FET and the photo-switching behavior of the flexible photo FETs. INTRODUCTION Recent advances have been achieved in organic electronics researches. Especially, improvements of device properties of Organic Field Effect Transistors (OFETs) and organic solar cells have been remarkable. We have fabricated OFETs having photo sensitivity and have utilized these devices for developing novel photo sensor and memory devices. Ordinary organic photo FETs are based on photo sensitivity of organic semiconductors used as an active layer [1,2]. However, we have developed organic photo FETs using photo sensitivities of insulator materials in FETs. Advantages of using photo sensitivities of insulator materials are to lower operating gate voltage, to raise on-off ratio, to raise µFET, and so on. Using these excellent device properties of the photo FETs, we are able to prepare high-sensitive photo sensor and memory devices. As photo-sensitive insulator material, 2,4,7-trinitrofluorenone (TNF) doped poly-(Nvinylcarbazole) (PVK) was employed. These materials are known as reliable photo receptors in the electrophotography field. In this report, we will discuss the development of the photo memory device by using the photo FET, and we will refer to the way to flexiblize the photo FET. EXPERIMENT Figure 1 (upper) shows the illustration of our newly developed photo FET structure that was fabricated as following procedure. An Indium Tin Oxide (ITO) glass was employed as a substrate and a transparent gate electrode. ITO glasses were carefully cleaned before the fabrication of FET devices. A PVK film was cast on the ITO glass from 0.33 wt.% chloroform solution as a photo-sensitive gate insulator. For sensitizing the PVK film to visible light, 2,4,7trinitro-9-fluorenone (TNF) was doped to the PVK film. Thickness of the cast PVK film resulted in ca. 1.5µm. For reducing a gate leakage current, a poly(vinyl phenol) (PVP) o
Data Loading...
