Remote sensing system for hydrogen using GaN Schottky diodes

Characterization of bulk GaN rectifiers for hydrogen gas sensing

“…4 for the reverse current characteristic and the resulting dependence of breakdown voltage on temperature. [25][26][27] Figure 6 shows the percentage change in forward current at forward bias of 1.0 V at room temperature as a function of H 2 concentration in N 2 .The response saturates above H 2 concentrations of ϳ200 ppm, which might be due to a limitation in supply of atomic hydrogen to the metal/GaN interface where it affects the interfacial charge and hence the effective barrier height. In the early stages of SiC rectifier development, the diodes also showed negative temperature coefficients of breakdown and the switch to the intrinsic positive coefficient was only seen as the defect density in the material was improved.…”

Recent advances in wide bandgap semiconductor-based gas sensors

“…The gate area of the HEMT can be used to modulate the drain current in the FET mode or for use as the electrode for the Schottky diode. A variety of gas, chemical and health-related sensors based on HEMT technology have been demonstrated with proper surface functionalization on the gate area of the HEMTs, including the detection of hydrogen, mercury ion, prostate specifi c antigen (PSA), DNA and glucose (Lothian et al, 1992;Luther et al, 1999;Johnson et al, 2000;Schalwig et al, 2002b;Eickhoff et al, 2003;Kim et al, 2003a;Mehandru et al, 2004;Pearton et al, 2004;Shen et al, 2004;Kang et al, 2004aKang et al, , 2004bKouche et al, 2005;Kryliouk et al, 2005;Tien et al, 2005aTien et al, , 2005bWang et al, 2005aWang et al, , 2005bWang et al, , 2005cKang et al, 2005bKang et al, , 2005cKang et al, 2006;Wang et al, 2006;Gangwani et al, 2007;Jun et al, 2007;Pearton et al, 2007;Kang et al, 2007aKang et al, , 2007bKang et al, , 2007cWang et al, , 2007cChen et al, 2008;Johnson et al, 2009;Yu et al, 2008;Wright et al, 2009).…”

“…The high electron sheet carrier concentration of nitride HEMTs is induced by piezoelectric polarization of the strained AlGaN layer and the spontaneous polarization is considerable in wurtzite III-nitrides. This provides an increased sensitivity relative to simple Schottky diodes fabricated on GaN layers (Baranzahi et al, 1995;Luther et al, 1999;Schalwig et al, 2001;Schalwig et al, 2002a;Kim et al, 2003;Weidemann et al, 2003;Kim et al, 2003b;Kang et al, 2004a;Kang et al, 2004b;Kouche et al, 2005;Matsuo et al, 2005;Voss et al, 2005;Wang et al, 2005;Yun et al, 2005;Song et al, 2005a;Song et al, 2005b;Ali et al, 2006;Huang et al, 2006). The gate area can be functionalized so that current changes can be detected for a variety of gases, liquids and biomolecules.…”

“…Hydrogen sensors are particularly interesting for the emerging fuel cell vehicle market. There are also applications for detection of combustion gases for fuel leak detection in spacecraft, automobiles and aircraft, fi re detectors, exhaust diagnosis and emissions from industrial processes (Baranzahi © Woodhead Publishing Limited, 2013Chen et al, 1998;Svenningstorp et al, 1999;Schalwig et al, 2002a;Eickhoff et al, 2003;Kim et al, 2004;Pearton et al, 2004;Kang et al, 2004a, Kouche et al, 2005Hung et al, 2012). A variety of gas, chemical and health-related sensors based on HEMT technology have been demonstrated with proper surface functionalization on the gate area of the HEMTs, including the detection of hydrogen, mercury ion, prostate specifi c antigen (PSA), DNA and glucose Wang et al, 2007c).…”

AlGaN/GaN High Electron Mobility Transistor Based Sensors for Bio-Applications

“…The gate region of the HEMT can be used to modulate the drain current in the FET mode or use as the electrode for the Schottky diode. A variety of gas, chemical and health-related sensors based on HEMT technology have been demonstrated with proper surface functionalization on the gate area of the HEMTs, including the detection of hydrogen, mercury ion, prostate specific antigen (PSA), DNA, and glucose [(Jun et al 2007, Yu et al 2008, Wang et al 2006a, Schalwig et al 2002, Luther, Wolter and Mohney 1999, Lim et al 2008, Tien et al 2005a, Kryliouk et al 2005, Eickhoff et al 2003, Mehandru et al 2004, Neuberger et al 2001, Gangwani et al 2007, Kouche et al 2005, Kang et al 2005d, Chen et al 2008, Kang et al 2004b, Lothian et al 1992, Johnson et al 2000, Kang et al 2006, Kang et al 2004a]. In this chapter, we discuss recent progress in the functionalization of these semiconductor sensors for applications in detection of pH measurement, biotoxins and other biologically important chemicals and the integration of these sensors into wireless packages for remote sensing capability.…”