Ultrahigh Sensitivity Self-Amplification Phototransistor Achieved by Automatic Energy Band Lowering Behavior

Author

Hua-Mao Chen ; Ting-Chang Chang ; Ya-Hsiang Tai ; Yu-Chun Chen ; Man-Chun Yang ; Cheng-Hsu Chou ; Jung-Fang Chang ; Shao-Zhi Deng

Author_Institution

Dept. of Photonics, Nat. Chiao Tung Univ., Hsinchu, Taiwan

Volume

61

Issue

9

fYear

2014

fDate

Sept. 2014

Firstpage

3186

Lastpage

3190

Abstract

In this paper, amorphous InGaZnO₄ thin-film transistors with an asymmetric structure exhibit ultraviolet (UV) light sensing property. At the offset region near the drain electrode, the extended active layer plays the role of a resistor. However, the ON-state current is obviously reduced with increasing offset length at the offset region near the source electrode and the characteristics cannot be turned ON when offset length is over 4 μm. After exposure to UV light, photogenerated holes-induce source barrier lowering and then amplifying the photocurrent response. Therefore, the devices in this paper reach a high-ON/OFF ratio of UV sensitivity to 10⁶.

Keywords

III-V semiconductors; gallium compounds; indium compounds; photoconductivity; photoemission; phototransistors; thin film transistors; wide band gap semiconductors; zinc compounds; InGaZnO₄; ON-OFF ratio; ON-state current; UV sensitivity; amorphous thin-film transistors; asymmetric structure; automatic energy band lowering behavior; extended active layer; photocurrent response; photogenerated holes; source barrier lowering; ultrahigh sensitivity self-amplification phototransistor; ultraviolet light sensing property; Educational institutions; Electrodes; Lighting; Logic gates; Thin film transistors; Voltage measurement; Amorphous InGaZnO₄ (a-InGaZnO₄); Amorphous InGaZnO4 (a-InGaZnO4); thin-film transistors (TFTs); ultraviolet (UV) sensor;

fLanguage

English

Journal_Title

Electron Devices, IEEE Transactions on

Publisher

ieee

ISSN

0018-9383

Type

jour

DOI

10.1109/TED.2014.2336235

Filename

6867311