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Boosted UV Photodetection Performance in Chemically Etched Amorphous Ga 2 O 3 Thin‐Film Transistors
Author(s) -
Han Zuyin,
Liang Huili,
Huo Wenxing,
Zhu Xiaoshan,
Du Xiaolong,
Mei Zengxia
Publication year - 2020
Publication title -
advanced optical materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.89
H-Index - 91
ISSN - 2195-1071
DOI - 10.1002/adom.201901833
Subject(s) - photodetection , materials science , responsivity , optoelectronics , photodiode , thin film transistor , photoconductivity , specific detectivity , photodetector , transistor , fabrication , amorphous solid , dark current , photosensitivity , nanotechnology , electrical engineering , medicine , alternative medicine , engineering , organic chemistry , pathology , chemistry , layer (electronics) , voltage
A three‐terminal thin‐film transistor (TFT) architecture is essential for photodetectors to reach a good balance between high responsivity and fast response speed. Bottom‐gate amorphous Ga 2 O 3 (a‐Ga 2 O 3 ) TFTs are fabricated to boost their UV photodetection properties. During the device fabrication process, a simple chemical‐etching solution with the advantages of easy operation, low cost, and compatibility with traditional lithography process, is developed to selectively etch a‐Ga 2 O 3 films. The a‐Ga 2 O 3 channel etched device on Si manifests an effective suppression of the commonly observed gate leakage current. Meanwhile, a patterned a‐Ga 2 O 3 TFT on quartz shows an excellent n‐type TFT performance with an on/off ratio as high as ≈10 7 . It is further applied as a phototransistor, to diminish the persistent photoconductivity (PPC) effect while keeping a high responsivity ( R ) as well. Under the 254 nm UV illumination, the a‐Ga 2 O 3 phototransistor demonstrates a high light‐to‐dark ratio of 5 × 10 7 , a high responsivity of 5.67 × 10 3 A W −1 , and a high detectivity of 1.87 × 10 15 Jones. Remarkably, the PPC phenomenon in a‐Ga 2 O 3 UV phototransistors is effectively suppressed by applying a positive gate pulse, which greatly shortens the decay time to 5 ms and offers a‐Ga 2 O 3 possible inroads into imaging applications.