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Abstract
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| The pH response of GaN/AlInN/AlN/GaN ion-sensitive field effect transistor (ISFET) on Si substrates has been characterized. We analyzed the variation of the surface potential (?Vsp/?pH) and current (?Ids/?pH) with solution pH in devices with the same indium content (17%, in-plane lattice-matched to GaN) and different AlInN thickness (6 nm and 10 nm), and compared with the literature. The shrinkage of the barrier, that has the effect to increase the transconductance of the device, makes the 2-dimensional electron density (2DEG) at the interface very sensitive to changes in the surface. Although the surface potential sensitivity to pH is similar in the two devices, the current change with pH (?Ids/?pH), when biasing the ISFET by a Ag/AgCl reference electrode, is almost 50% higher in the device with 6 nm AlInN barrier, compared to the device with 10 nm barrier. When measuring the current response (?Ids/?pH) without reference electrode, the device with thinner AlInN layer has a larger response than the thicker one, of a factor of 140%, and that current response without reference electrode is only 22% lower than its maximum response obtained using reference electrode. | |
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International
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Si |
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JCR
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Si |
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Title
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Sensors And Actuators B-Chemical |
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ISBN
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0925-4005 |
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Impact factor JCR
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3,898 |
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Impact info
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Datos JCR del año 2011 |
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Volume
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176 |
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Journal number
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From page
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704 |
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To page
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707 |
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Month
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SIN MES |
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Ranking
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