Organic vapour sensing by current response of porous silicon layer

• Published in: Journal of physics. D, Applied physics Applied physics, 2001-12, Vol.34 (24), p.3505-3509
• Main Authors: Kim, Seong-Jeen, Lee, Sang-Hoon, Lee, Cheol-Jin
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Chemistry; Exact sciences and technology; General equipment and techniques; General, instrumentation; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Physics; Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
• ISSN: 0022-3727; 1361-6463
• DOI: 10.1088/0022-3727/34/24/314

In this paper, a porous silicon (PS) layer is investigated as a sensing material to detect organic vapors with low concentration. To do this, PS sensors with membrane structure were designed and fabricated. The sensors were made by applying the technologies of membrane formation by anisotropic etching of silicon and PS formation by anodization in HF solution. From fabricated sensors, current-voltage (I-V) curves were measured for ethanol (called alcohol), methanol, and acetone gases evaporated from 0.1-0.5 percent solution concentrations at 36 C. As a result, all curves showed rectifying behavior due to a diode structure between Si and the PS layer. The conductance of our sensors mostly increased along with the organic solution concentration at a high voltage of 5 V, but the built-in potential on the measured I-V curve was lowered with it by the adsorption effect of the organic vapors with high dipole moment. (Author)