Open-gated ph sensor fabricated on an undoped-algan/gan hemt structure
The sensing responses in aqueous solution of an open-gated pH sensor fabricated on an AlGaN/GaN high-electron-mobility-transistor (HEMT) structure are investigated. Under air-exposed ambient conditions, the open-gated undoped AlGaN/GaN HEMT only shows the presence of a linear current region. This se...
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2011
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my.utm.297362017-10-17T04:55:36Z http://eprints.utm.my/id/eprint/29736/ Open-gated ph sensor fabricated on an undoped-algan/gan hemt structure Zainal Abidin, Mastura Shafinaz Hashim, Abdul Manaf Sharifabad, Maneea Eizadi Abd. Rahman, Shaharin Fadzli Sadoh, Taizoh TK Electrical engineering. Electronics Nuclear engineering The sensing responses in aqueous solution of an open-gated pH sensor fabricated on an AlGaN/GaN high-electron-mobility-transistor (HEMT) structure are investigated. Under air-exposed ambient conditions, the open-gated undoped AlGaN/GaN HEMT only shows the presence of a linear current region. This seems to show that very low Fermi level pinning by surface states exists in the undoped AlGaN/GaN sample. In aqueous solution, typical current-voltage (I-V) characteristics with reasonably good gate controllability are observed, showing that the potential of the AlGaN surface at the open-gated area is effectively controlled via aqueous solution by the Ag/AgCl gate electrode. The open-gated undoped AlGaN/GaN HEMT structure is capable of distinguishing pH level in aqueous electrolytes and exhibits linear sensitivity, where high sensitivity of 1.9 mA/pH or 3.88 mA/mm/pH at drain-source voltage, VDS = 5 V is obtained. Due to the large leakage current where it increases with the negative gate voltage, Nernstian like sensitivity cannot be determined as commonly reported in the literature. This large leakage current may be caused by the technical factors rather than any characteristics of the devices. Surprisingly, although there are some imperfections in the device preparation and measurement, the fabricated devices work very well in distinguishing the pH levels. Suppression of current leakage by improving the device preparation is likely needed to improve the device performance. The fabricated device is expected to be suitable for pH sensing applications. Molecular Diversity Preservation International 2011 Article PeerReviewed Zainal Abidin, Mastura Shafinaz and Hashim, Abdul Manaf and Sharifabad, Maneea Eizadi and Abd. Rahman, Shaharin Fadzli and Sadoh, Taizoh (2011) Open-gated ph sensor fabricated on an undoped-algan/gan hemt structure. SENSORS, 11 (1). pp. 3067-3077. ISSN 1424-8220 http://dx.doi.org/10.3390/s110303067 10.3390/s110303067 |
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TK Electrical engineering. Electronics Nuclear engineering Zainal Abidin, Mastura Shafinaz Hashim, Abdul Manaf Sharifabad, Maneea Eizadi Abd. Rahman, Shaharin Fadzli Sadoh, Taizoh Open-gated ph sensor fabricated on an undoped-algan/gan hemt structure |
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The sensing responses in aqueous solution of an open-gated pH sensor fabricated on an AlGaN/GaN high-electron-mobility-transistor (HEMT) structure are investigated. Under air-exposed ambient conditions, the open-gated undoped AlGaN/GaN HEMT only shows the presence of a linear current region. This seems to show that very low Fermi level pinning by surface states exists in the undoped AlGaN/GaN sample. In aqueous solution, typical current-voltage (I-V) characteristics with reasonably good gate controllability are observed, showing that the potential of the AlGaN surface at the open-gated area is effectively controlled via aqueous solution by the Ag/AgCl gate electrode. The open-gated undoped AlGaN/GaN HEMT structure is capable of distinguishing pH level in aqueous electrolytes and exhibits linear sensitivity, where high sensitivity of 1.9 mA/pH or 3.88 mA/mm/pH at drain-source voltage, VDS = 5 V is obtained. Due to the large leakage current where it increases with the negative gate voltage, Nernstian like sensitivity cannot be determined as commonly reported in the literature. This large leakage current may be caused by the technical factors rather than any characteristics of the devices. Surprisingly, although there are some imperfections in the device preparation and measurement, the fabricated devices work very well in distinguishing the pH levels. Suppression of current leakage by improving the device preparation is likely needed to improve the device performance. The fabricated device is expected to be suitable for pH sensing applications. |
format |
Article |
author |
Zainal Abidin, Mastura Shafinaz Hashim, Abdul Manaf Sharifabad, Maneea Eizadi Abd. Rahman, Shaharin Fadzli Sadoh, Taizoh |
author_facet |
Zainal Abidin, Mastura Shafinaz Hashim, Abdul Manaf Sharifabad, Maneea Eizadi Abd. Rahman, Shaharin Fadzli Sadoh, Taizoh |
author_sort |
Zainal Abidin, Mastura Shafinaz |
title |
Open-gated ph sensor fabricated on an undoped-algan/gan hemt structure |
title_short |
Open-gated ph sensor fabricated on an undoped-algan/gan hemt structure |
title_full |
Open-gated ph sensor fabricated on an undoped-algan/gan hemt structure |
title_fullStr |
Open-gated ph sensor fabricated on an undoped-algan/gan hemt structure |
title_full_unstemmed |
Open-gated ph sensor fabricated on an undoped-algan/gan hemt structure |
title_sort |
open-gated ph sensor fabricated on an undoped-algan/gan hemt structure |
publisher |
Molecular Diversity Preservation International |
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2011 |
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http://eprints.utm.my/id/eprint/29736/ http://dx.doi.org/10.3390/s110303067 |
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