A study of silicon Schottky diode structures for NOx gas detection

A silicon Schottky diode structure was applied for detecting nitride oxide gases at room temperature. The Pt–Pd/Si/Al structure was employed successfully to detect NO2 gas concentration for as low as 6 ppm at room temperature. This sensor also showed useful response to NO gas, but the sensitivity was lower than its sensitivity to NO2 gas. Fabrication of the diode on a porous silicon surface enhances NO2 gas sensitivity, but the response time becomes longer. This structure provides a convenient technique to manufacture miniaturized and integrated sensors.