Monitoring of HF and F2 using a field-effect sensor

Detection of hydrogen fluoride using SnO2-based gas sensors: Understanding of the reactional mechanism

“…-Second, the XPS study of the sample labelled "annealing" (see Table 1) showed that the chemisorption of fluorine on the tin atoms is reversible. This means that at high temperatures, fluorine may desorb from tin atoms which is in agreement with Moritz et al results [11].…”

Field-effect sensor for the selective detection of fluorocarbons

“…For this point of view we need not consider the thermodynamics of the species in the gaseous phase but have to assume that unstable species can be stabilised at the interface. It is very important for this mechanism that a¯uoride ion can be introduced to a defect (ion vacancy) of LaF 3 . We have proven the existence of a three-phase boundary LaF 3 /Pt/gas for the structures under investigation [11].…”

“…The nickel cell had an aluminium oxide insulator and was heated by an external oven. The free volume of the cell was less than 0.2 cm 3 . The rear and top side contacts of the sensor (sample) holder were made of platinum and graphite, respectively.…”

“…Recently, we developed a ®eld-effect semiconductor sensor for the detection of¯uorine and hydrogen¯uoride in atmospheric air as well as in inert gases [3,4]. This sensor is a metal/insulator/semiconductor (MIS) device and has a structure Si/SiO 2 /Si 3 N 4 /LaF 3 /Pt.…”

Direct Observation of Platinum Etching during the Fluorination of a Pt/LaF3/Si Structure

“…Recently we have developed gas sensors for the determination of oxygen, fluorine or hydrogen fluoride using a structure Pt/LaF 3 /Si [8 to 12]. This fluorine sensor has been proven to be very stable and advantageous concerning a very steep capacitance-voltage (C±V) curve, but the stability of this sensor depends on the properties of the three-phase boundary formed by gas, platinum and lanthanum trifluoride [10,11]. Therefore on one hand, the influence of fluorine on the Pt/LaF 3 /Si structure is very important because it leads to a change of the electrochemical potential in such structures and, on the other hand, this is of interest because of its importance in understanding the fundamentals of gas-surface interactions and, especially, because of its direct relevance to etching of platinum.…”