A hydrogen gas sensitive Pt-In0.5A10.5P metal-semiconductor Schottky diode

A new and interesting compound semiconductor Schottky diode hydrogen sensor based on a Pt-In0.5Al0.5P metal-semiconductor (MS) structure is fabricated and demonstrated. The hydrogen sensing characteristics including hydrogen detection sensitivity of the studied device under different hydrogen concentrations and temperature are measured and studied. The hydrogen detection sensitivity is related to a change in the contact potential at the Pt-semiconductor interface. Experimentally, the studied hydrogen sensor can be operated systematically under the applied bi-polarity voltage biases. When the temperature is increased from 30 to 250degC, the hydrogen relative sensitivity ratio (Sr), under the applied forward (reverse) bias of 0.3 V, is decreased from 181.2% (250.3%) to 28.2% (33.5%) upon exposing to the 9970 ppm H2/air gas. Moreover, the hydrogen effect in the Schottky barrier height lowering is observed.