Effect of depletion layer width on electrical properties of semiconductive thin film gas sensor: a numerical study based on the gradient-distributed oxygen vacancy model

Abstract

The effects of depletion layer width on the semiconductor gas sensors were investigated based on the gradient-distributed oxygen vacancy model, which provided numerical descriptions for the sensor properties. The potential barrier height, sensor resistance, and response to target gases were simulated to reveal their dependences on the depletion layer width. According to the simulation, it was possible to improve the sensor response by enlarging the width of depletion layer without changing the resistance of the gas sensor under the special circumstance. The different performances between resistance and response could provide a bright expectation that the design and fabrication of gas sensing devices could be economized. The simulation results were validated by the experimental performances of SnO 2 thin film gas sensors, which were prepared by the sol-gel technique. The dependences of sensor properties on depletion layer width were observed to be in agreement with the simulations.

Size effect on oxygen vacancy formation and gaseous adsorption in ZnO nanocrystallites for gas sensors: a first principle calculation study

“…In terms of theoretical researches, N. Yamazoe proposed the theory of power law, which described the crystallite size effect in the dependence of response on H 2 concentration [21]. The model of gradient distributed oxygen vacancies was proposed by J. Liu and it quantitatively illustrated the significant enhancement of semiconductor resistance and response when the crystallite size was reduced to be comparable to the depletion layer width [20,[31][32][33]. The conclusion was in agreement with C. Xu's work.…”

Influence of Oxygen Vacancy Behaviors in Cooling Process on Semiconductor Gas Sensors: A Numerical Analysis

“…Furthermore, the influences of the cooling rate on the gas sensor properties are concluded in this work. Compared with previous research [ 33 , 34 , 44 ], the present results provide a more precise description of V O behaviors during the cooling process. Therefore, it is possible to calculate the gas-sensing properties of the sensors prior to practical fabrication and the calculation results are beneficial for the design of sensor preparation.…”

“…A diffusion equation of V O migration was established in a one-dimensional model based on the diffusion and exclusion effects. In the previous studies [ 33 , 34 , 44 ], the parameter of T E (end temperature of cooling process) had to be used to find the analytical solutions of the diffusion equation. This approximation is helpful to mathematical conduction but leads to an inaccuracy in the calculation results.…”

Roles of structure and electron mobilization in enhanced ethanol sensing by Al doped SnO2nanoparticles

“…Hence, while all the factors above cumulatively decide the fate of the sensing response, the plausible mechanism of chemiresistive sensing has mostly been based on the charge depletion model or the band bending concepts. [9][10][11][12][13] But all the concepts mentioned above give a qualitative idea of the electron dynamics involved in the sensor material and hence visualizing gas sensing from a more fundamental background seems difficult. [14][15][16] While electrons play the major role in all events during chemiresistive sensing, 17,18 it is necessary to address both qualitative as well as quantitative analyses of their distribution within the system to understand the sensing mechanism.…”