Finite difference solution of the diffusion equation describing the response and recovery of thin film semiconductor gas sensors

Gas diffusion dynamics of a thin film semiconductor gas sensor is investigated by solving the relevant diffusion equation using the explicit finite difference method. Concentration profiles of the target gas inside the film are determined at various times during the transient process, both during the response stage when the target gas is being supplied and during the recovery stage when this supply is discontinued. Results are compared to analytical solution reported in the literature and good agreement is found. It is shown that the explicit finite difference method is effective and accurate for solving the diffusion equation describing the response and recovery process of a thin film semiconductor gas sensor, which is specially important when arbitrary initial and boundary conditions are required.