Sensitivity Analysis of Pd-MOS Structure for Hydrogenated Gases by Scanning Light Pulse Technique

Abstract

This paper presents an analysis of the performance of a Pd-MOS structure with respect to their sensitivity to hydrogenated gases. Assays using an experimental arrangement of the scanning light pulse technique (SLPT) were carried out. This arrangement allowed the chemical images patterns generation that show the sensitivity of the device to different gas composition, which the sensor was exposed.

The MOS Device Applied to Hydrogenated Gas Sensor Device

“…The second important result, observed from the chemical images, is related to different sensibility response for H 2 and ECS Transactions, 49 (1) 465-472 (2012) NH 3 gases, the highest response intensity was observed for H 2 gas. This result is happened because the H 2 molecules decomposition at Pd metal happens in one step process however, the NH 3 decomposition need another intermediate reaction (10). The third important aspect observed from the chemical images pointed out the different sensor response when used N 2 or dry air as a carrier gas.…”

“…In this sense as described in the experimental procedure, the MOS sensor was made with wind vane patter gate composed for Pd, Pt and Au metal (Figure 1). On this device the chemical image were obtained by using scanned light pulse technique detailed everywhere (10). This light pulse create the e-h pairs in the silicon substrate but only the carrier created at depletion layer contributed to external photocurrent pulse.…”

Nano-Crystalline Palladium-Film Catalysts Deposited By E-beam Evaporation Aiming Hydrogen Sensing

“…The operation range of palladium-based sensors is generally limited to temperatures around 100 o C (14,15) in order to avoid damages in the crystalline structure of the film and consequently, in the recovering time of the devices. The hydrogen diffusion through the film and ocupation of interstitial lattice sites causes an increase in electron scattering; and therefore, an increase in the resistance (16).…”

“…Moreover, hydrogen is considered as a powerful alternative energy source and has been widely studied for many researchers throughout the years (5,6). Meanwhile, the hydrogen gas can not be detected by the human olfative system (from 4% to 75%) (7), and is highly inflamable making the development of sensors imperative, (8,9,10,11,12,13,14,15). This work is focused on the development of palladium-film catalysts deposited by e-beam evaporation technique and on the evaluation of their behavior in hydrogen sensing after annealing under air and forming gas expositions.…”