Ultrafast H2 gas nanosensor for ppb-level H2 gas detection based on GaN honeycomb nanonetwork

• Published in: Sensors and actuators. B, Chemical Vol. 329; p. 129079
• Main Authors: Zhong, Aihua, Shen, Bowei, Wang, Tao, Jin, Hao, Xie, Yizhu, Zhang, Dongping, Li, Huayao, Liu, Huan, Luo, Jingting, Fan, Ping
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 15.02.2021; Elsevier Science Ltd
• Subjects: Density functional theory; Field effect transistor; Field effect transistors; Gallium nitrides; GaN; Gas sensors; Hydrogen gas sensor; Nanosensors; Platinum; Response time; Semiconductor devices; Sensors; Field effect transistor; Response time; Hydrogen gas sensor; GaN
• DOI: 10.1016/j.snb.2020.129079
• ISSN: 0925-4005

[Display omitted] •Employment of GaN honeycomb nanonetwork for the FET type H2 gas sensor.•Demonstration of a H2 sensor with small LOD ∼34 ppb and fast response ∼3 s.•Employment of Pt nanonetwork as the catalyst for H2 gas dissociation.•First discovery of electron tunneling effect during H2 gas detection. Material architecture design plays a crucial role in developing gas sensors. GaN has been proposed as a promising material for H2 gas sensor. However, it is subject to long response time and large low limit of detection (LOD).via spherical metal pattern technology, honeycomb can be created in GaN nanostructure but has yet to be explored. Herein, the GaN honeycomb nanonetwork was utilized to fabricate a field effect transistor (FET) type hydrogen (H2) gas nanosensor and its H2 gas sensing performances were systematically investigated. Through the combination of the novel honeycomb nanonetwork with the field effect modulation, we demonstrate high performance H2 gas sensor with wide detection concentration range, fast response, and small LOD. It is worth noting that the response time for H2 gas is very fast, as short as ≤3 s. Most importantly, the LOD for this FET type sensor is as small as ∼ 34 ppb. Density functional theory (DFT) calculation was utilized to study the H2 gas sensing mechanism. Significant reduction of Schottky barrier and improvement of the tunneling probability of the Pt-GaN metal-semiconductor interface were observed. Finally, a model is proposed to explain the H2 gas sensing mechanism.