Hydrogen sensitive Schottky diode using semipolar (1 1 (2)over-bar 2) AlGaN/GaN heterostructures

초록

In this work, we investigated the hydrogen sensing characteristics of Pt Schottky diodes using semipolar (1 1 (2) over bar 2) AlGaN/GaN structures. First, these diodes showed a large current change of 30 mA at 1 V upon the introduction of 4% hydrogen in nitrogen gas with an accompanying Schottky barrier reduction of 90 meV at 25 degrees C. Second, their hydrogen detection sensitivity peaked at the zero bias voltage, and slowly decreased with applied bias voltage. Third, they demonstrated stable and reproducible current changes with a reasonable linearity in response to H-2 concentrations from 0.5 similar to 4% with a step of 0.5%. As such, Pt Schottky diodes on semipolar AlGaN/GaN structures hold great promise for highly-sensitive hydrogen sensors due to their surface polarity and atomic configuration. (C) 2015 Elsevier B.V. All rights reserved.

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