Home >

news Help

Publication Information


Title
Japanese: 
English:High-density carrier accumulation in ZnO field-effect transistors gated by electric double layers of ionic liquids 
Author
Japanese: 袁 洪涛, 下谷 秀和, 塚崎 敦, 大友 明, 川崎 雅司, 岩佐 義宏.  
English: H. T. Yuan, H. Shimotani, A. Tsukazaki, A. Ohtomo, M. Kawasaki, Y. Iwasa.  
Language English 
Journal/Book name
Japanese: 
English:Advanced Functional Materials 
Volume, Number, Page Vol. 19    No. 7    pp. 1046-1053
Published date Apr. 2009 
Publisher
Japanese: 
English: 
Conference name
Japanese: 
English: 
Conference site
Japanese: 
English: 
Official URL <Go to ISI>://000265394900008
 
DOI https://doi.org/10.1002/adfm.200801633
Abstract Very recently, electric-field-induced superconductivity in an insulator was realized by tuning charge carrier to a high density level (1 x 1014) cm-2). To increase the maximum attainable carrier density for electrostatic tuning of electronic states in semiconductor field-effect transistors is a hot issue but a big challenge. Here, ultrahigh density carrier accumulation is reported, in particular at low temperature, in a ZnO field-effect transistor gated by electric double layers of ionic liquid (IL). This transistor, called an electric double layer transistor (EDLT), is found to exhibit very high transconductance and an ultrahigh carrier density in a fast, reversible, and reproducible manner. The room temperature capacitance of EDLTs is found to be as large as 34 mu F cm-2, deduced from Hall-effect measurements, and is mainly responsible for the carrier density modulation in a very wide range. Importantly, the IL dielectric, with a supercooling property, is found to have charge-accumulation capability even at low temperatures, reaching an ultrahigh carrier density of 8 x 1014 cm-2 at 220 K and maintaining a density of 5.5 x 1014 cm-2 at 1.8 K. This high carrier density of EDLTs is of great importance not only in practical device applications but also in fundamental research; for example, in the search for novel electronic phenomena, such as superconductivity, in oxide systems.

©2007 Tokyo Institute of Technology All rights reserved.