High‐Performance, Transparent Thin Film Hydrogen Gas Sensor Using 2D Electron Gas at Interface of Oxide Thin Film Heterostructure Grown by Atomic Layer Deposition. (11th December 2018)

• Record Type: Journal Article
• Authors: Kim, Sung Min; Kim, Hye Ju; Jung, Hae Jun; Park, Ji‐Yong; Seok, Tae Jun; Choa, Yong‐Ho; Park, Tae Joo; Lee, Sang Woon
• Is Part Of: Advanced functional materials. Volume 29:Number 7(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-12-11
• Subjects: atomic layer deposition -- gas sensor -- hydrogen -- oxide heterostructure -- thin film; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.201807760
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: A high‐performance, transparent, and extremely thin (<15 nm) hydrogen (H2 ) gas sensor is developed using 2D electron gas (2DEG) at the interface of an Al2 O3 /TiO2 thin film heterostructure grown by atomic layer deposition (ALD), without using an epitaxial layer or a single crystalline substrate. Palladium nanoparticles (≈2 nm in thickness) are used on the surface of the Al2 O3 /TiO2 thin film heterostructure to detect H2 . This extremely thin gas sensor can be fabricated on general substrates such as a quartz, enabling its practical application. Interestingly, the electron density of the Al2 O3 /TiO2 thin film heterostructure can be tailored using ALD process temperature in contrast to 2DEG at the epitaxial interfaces of the oxide heterostructures such as LaAlO3 /SrTiO3 . This tunability provides the optimal electron density for H2 detection. The Pd/Al2 O3 /TiO2 sensor detects H2 gas quickly with a short response time of <30 s at 300 K which outperforms conventional H2 gas sensors, indicating that heating modules are not required for the rapid detection of H2 . A wide bandgap (>3.2 eV) with the extremely thin film thickness allows for a transparent sensor (transmittance of 83% in the visible spectrum) and this fabrication scheme enables the development of flexible gas sensors. Abstract : A high‐performance, transparent, and extremely thin (≈15 nm) hydrogen (H2 ) gas sensor is developed using 2D electron gas at the interface of an Al2 O3 /TiO2 thin film heterostructure. This extremely thin gas sensor can be fabricated on general substrates such as a glass using atomic layer deposition, and this fabrication scheme enables the development of flexible gas sensors.