Metal oxide semiconductor-based gas sensors with nanosized grain have significantly high gas sensitivity as compared with the larger grain counterparts. A numerical model has been presented to recognize the role of different sizes of nanocrystallites of n-type SnO₂ semiconductors as gas sensors. The potential profile inside the spherical grains as a function of grain size, temperature and density of surface states has been calculated. Wolkenstein approach for dissociative chemical adsorption of environmental oxygen has been adopted for all calculations. Both full and partial depletion approximations have been considered to review the potential in spherical nanograins. This model is based on the analytical solution of Poisson’s equation in spherical coordinates and numerical solution of the electroneutrality condition. Effect of normalized potential on the charge transfer at the available surface states has been calculated. Present work discusses the phenomenon of energy band flattening for smaller nanocrystals. In spherical nanosized grains, the sharp change in the potential at the grain centre at a fixed value of surface state density has been explained. Calculations for carrier concentrations and normalized gas sensor response as a function of nanosized grains have been carried out and explained on the basis of different experimental observations.

与较大的晶粒对应物相比，具有纳米晶粒的基于金属氧化物半导体的气体传感器具有显着高的气体敏感性。提出了一个数值模型来认识不同大小的n型SnO ₂纳米晶体的作用半导体作为气体传感器。已经计算出球形晶粒内部的电势轮廓随晶粒尺寸，温度和表面态密度的变化。所有计算都采用了Wolkenstein方法对环境氧进行解离化学吸附。已经考虑了全部和部分耗尽近似来回顾球形纳米颗粒的潜力。该模型基于泊松方程在球坐标系下的解析解和电中性条件的数值解。已经计算出归一化电势对可用表面态电荷转移的影响。目前的工作讨论了较小的纳米晶体能带变平的现象。在球形纳米颗粒中，已经解释了在表面状态密度为固定值时晶粒中心处电势的急剧变化。已经根据不同的实验观察结果进行了载流子浓度和归一化气体传感器响应随纳米颗粒的变化的计算，并进行了解释。