Distinction of gases with a semiconductor sensor depending on the scanning profile of a cyclic temperature

Abstract

A gas-sensing system based on a dynamic nonlinear response is reported to improve the selectivity in the sensor response toward sample gases. A cyclic temperature composed of fundamental and second harmonics was applied to a SnO(2) semiconductor gas sensor and the resulting conductance of the sensor was analyzed by fast Fourier transformation (FFT). The dynamic nonlinear responses to the gas species were further characterized depending on the scanning profile of the temperature. These characteristic sensor responses under the application of second-harmonic perturbation were theoretically considered based on a reaction-diffusion model for the semiconductor surface.

Distinguishing Among Gases with a Semiconductor Sensor Depending on the Frequency Modulation of a Cyclic Temperature

“…The conductance of a semiconductor gas sensor, G(T), depends on the surface Schottky barrier height V s and temperature, since the conductance of a SnO 2 semiconductor gas sensor may be considered a model of barrier-limited conductance [1,3,12,22,26,27]:…”

“…To clarify the dynamic sensor responses under the application of frequency modulation of a cyclic temperature, a numerical simulation of the sensor response was performed based on the following model for a semiconductor gas sensor [1,3,12,22,26,27]:…”

“…The characteristic nonlinear responses of a semiconductor gas sensor under the application of temperature perturbation including frequency modulation were not only evaluated by a polynomial approximation but also calculated based on a reaction-diffusion model for the solid surface. Figure 1 shows a schematic representation of the experimental apparatus developed from our previous system, and processes (1) and (2) were performed [3,16,21,22]. Process (2) was developed in this paper.…”

Harnessing self-heating in nanowires for energy efficient, fully autonomous and ultra-fast gas sensors

“…On the one hand and from the point of view of the sensor selectivity, the possibility to follow response signals in the range of 100 Hz enables the development of faster separation algorithms based on cycling temperature profiles [19,20]. On the other hand and from the power consumption perspective, the fast dynamics demonstrates that it is possible to dramatically reduce the already Fig.…”

“…Therefore, sensors based on individual nanowires are generally faster devices than their micro-counterparts [17]. This advantage, combined with the rapid thermal response of the self-heating effect, compelled us to prove the feasibility of developing novel pulsed-operated devices with superior analytical capabilities [19,20] and even lower power requirements [10].…”