A study on a palladium-titanium oxide Schottky diode as a detector for gaseous components

Highly hydrogen-sensitive SnO2 nanoscale-particle films with platinum electrodes

“…H 2 molecules adsorbed on the Pt or the Pd electrode surface are believed to break into hydrogen atoms which migrate into the metal bulk or even to the metal-oxide (n-type) contact, reducing the work function of the metal and therefore lowering the Schottky barrier height (SBH) at the metal/oxide interface. This effect has been studied and applied to develop hydrogen sensors based on Pd (or Pt)/SiO 2 MOS structures [47], as well as those based on Pd (or Pt)/TiO 2 (or SnO 2 ) Schottky diodes [48][49][50][51][52][53][54]. Although fabrication of Pd (or Pt)/TiO 2 Schottky devices and their sensing properties to reactive gases were thoroughly investigated during the last two decades [49][50][51]53,54], gas-sensing studies on Pt/SnO 2 diodes were much less frequently reported than the former.…”

“…This effect has been studied and applied to develop hydrogen sensors based on Pd (or Pt)/SiO 2 MOS structures [47], as well as those based on Pd (or Pt)/TiO 2 (or SnO 2 ) Schottky diodes [48][49][50][51][52][53][54]. Although fabrication of Pd (or Pt)/TiO 2 Schottky devices and their sensing properties to reactive gases were thoroughly investigated during the last two decades [49][50][51]53,54], gas-sensing studies on Pt/SnO 2 diodes were much less frequently reported than the former. The research of gas-sensitive Pt/SnO 2 devices is focused on varistors [55,56], in which the sensing mechanism is not the reduction of the barrier height at the Pt/SnO 2 interface but the lowering of barriers between SnO 2 grains.…”

Room temperature liquefied petroleum gas (LPG) sensor

“…Thus the carrier concentration of the heterojunction decreases and current across the junction decreases and consequently barrier height of the heterojunction increases when exposed to LPG, contrast to hydrogen gas sensors based on Pd/TiO 2 [27]. The change in current may be due to the chemical reaction between interface of heterojunction and adsorbed gas molecules.…”

Feasibility Study on Advanced Solid-State Oxygen Sensors.

“…Recently there have been many reports about ion-sensitive MIS (metalinsulator-semiconductor) (69) or MOS (metal-oxide-semiconductor) devices, with special interest on the structure which includes capacitors (70)(71)(72)(73)(74), diodes (75)(76)(77)(78), and transistors (79)(80)(81)(82)(83)(84)(85)(86)(87)(88). These devices are mainly designed to detect hydrogen and are known to work well with catalytic metals such as Pd and Pt on the oxide material.…”

“…Yamamoto (75) used Pd and TiO 2 (which is typically used as an oxygensensor ceramic) to design a hydrogen-sensitive device (Fig. 26).…”