A Novel $\hbox{Pt/In}_{0.52}\hbox{Al}_{0.48}\hbox{As}$ Schottky Diode-Type Hydrogen Sensor
On the basis of a Pt/In0.52Al0.48As metal-semiconductor structure, a novel hydrogen sensor is fabricated and demonstrated. The studied Pt/In0.52Al0.48As Schottky diode-type hydrogen sensor exhibits significant sensing performance including high relative sensitivity ratio of about 2600% (under the 1% H2/air gas and VR=-0.5 V at 30 degC), large current variation of 310 muA (under the 1% H2/air gas and VR=-5 V at 200 degC), widespread reverse-voltage regime (0~-5 V), stable hydrogen-sensing current-voltage (I-V) curves, and fast transient response time of 1.5 s. The calculated Schottky barrier-height change and series-resistance variation, from the thermionic-emission model and Norde method, are 87.0 meV and 288 Omega, respectively (under the 1% H2/air gas at 30 degC). The hydrogen concentrations and operating temperatures tested in this letter are in the range of 15 ppm-1% H2/air and 30 degC-250 degC, respectively. Based on the excellent integration compatibility with InP-based electronic devices, the studied device provides the potentiality in high-performance sensor-array applications
Composition-modulated electrodeposited PdNi-Si hydrogen sensors for low power applications
This work presents a Schottky barrier based PdNi-Si hydrogen sensor for distributed wireless sensor networks with extremely low power consumption. It is shown that a variation of the electrodeposition potential is capable of creating PdNi alloys with the ratio of Pd to Ni spanning almost the entire range. Based on this, we utilise the technique of composition-modulation, in which each part of the PdNi film is separately optimized within a single electrodeposition run for use in a Schottky barrier hydrogen sensor. The sensors have full specificity with respect to nitrogen and oxygen, and a sensitivity of 1.5%/ppm at 1000ppm H2. The time response to 90% of the final signal is reached in around 100s at 1000 ppm H2.
The Schottky‐barrier height of Au on n‐Ga1−xAlxAs as a function of AlAs content
The Schottky‐barrier height of Au on chemically etched n‐Ga1−xAlxAs was measured as a function of x. As x increases, the barrier height rises to a value of about 1.2 eV at x≈0.45, then decreases to about 1.0 eV as x approaches 0.83. The barrier height deviates in a linear way from the value predicted by the ’’common‐anion’’ rule as the AlAs mole fraction increases. This behavior is related to chemical reactivity of the Ga1−xAlxAs surface.