National Science Council

Hsi-Jen Pan

Wen-Chau Liu

Huey-Ing Chen

Yen-I Chou

Huey-lng Chen

Chin-Yi Chu

A high-sensitivity Pd/InP hydrogen sensor was made by a) forming an n-type or p-type semiconductor film on a semiconductor substrate; b) forming a patterned first metal electrode on the semiconductor film, wherein the first metal electrode forms an Ohmic contact with the semiconductor film; and c) forming a second metal electrode on the semiconductor film, the second metal electrode being isolated from the first metal electrode, wherein the second metal electrode forms a Schottky contact with the semiconductor film, wherein a thickness of the second metal electrode and a material of which the second metal electrode is made enable a Schottky barrier height of the Schottky contact to decrease when hydrogen contacts the second metal electrode. The second metal electrode can be physical vapor deposited or electroless plated.

Process for preparing a hydrogen sensor

In this invention, we propose a high-sensitivity Pd/InP hydrogen sensor. First, a n-type InP semiconductor membrane is grown on a semi-insulating InP substrate. The concentration and thickness of this membrane are 2&times;10,cm,and 3000 &angst;, respectively. Then, Pd metal and AuGe alloy are evaporated on the surface of the membrane as the anode and cathode electrodes, respectively. Due to the catalytic performance of Pd metal, the adsorbed hydrogen molecules on the surface of the Pd metal are dissociated into hydrogen atoms. The hydrogen atoms diffuse and pass through the Pd metal and form a dipole layer at the interface between the Pd metal and the n-type InP membrane. This dipole layer will decrease the depletion width of the n-type InP membrane and further lower the metal-semiconductor Schottky barrier height. Therefore, the current-voltage (I-V) characteristics will be modulated after the introduction of hydrogen gas.

Growing community of inventors

Tainan, Taiwan

Hsi-Jen Pan