Content area
Full text
Introduction
Gas sensors have carved out their own niche due to the widespread use of gases in households and automobiles. Developing effective gas sensors for strategic placement in critical areas is crucial to prevent hazardous accidents resulting from the leakage of flammable or toxic gases. Metal oxide semiconductor (MOS) sensors have emerged as a top choice for commercial sensor development due to their good stability, high sensitivity, low cost and ease of synthesis [1, 2–3]. SnO2 is the most extensively researched MOS due to its excellent gas sensing performance [4, 5–6]. With its improved capacity to adsorb oxygen on its surface, SnO2 emerges as a promising material for gas sensing applications. SnO2 has a wide, direct band gap of 3.6 eV at room temperature. It generally has a tetragonal (rutile) structure, characterized by lattice parameters of a = b = 4.737 Å and c = 3.186 Å. Extensive structural and morphological studies have been conducted on SnO2. The goal of these studies is to understand and manipulate its structural and morphological features to optimize its performance as a gas sensor. Attempts have been made to increase the surface-to-volume ratio of SnO2 to boost its gas sensing capabilities. Research is underway to synthesis nanostructures or porous structures of basic SnO2 material which will enhance the gas adsorption. Zero dimensional and one dimensional sensing materials are explored to understand the favorable morphologies suitable for gas sensing [7] and thus research has focused on modifying the structural properties of SnO2 to achieve an enhanced gas sensing response [8, 9–10]. Yoshitake Masuda has highlighted the impact of dimension and morphology on sensing performance and provided guidelines for enhancing it. These recommendations include minimizing the crystallite size of oxide semiconductors, finely dispersing sensitizers, and optimizing the thickness and porosity of the sensing layer to enhance selectivity and durability [11]. Kong et al. reported that nanomaterials can greatly influence gas-sensitive properties due to their quantum size effects, surface characteristics, and overall small size effects [12]. Similar to structural properties, optical properties of SnO2, have also been studied and correlated with gas sensing performance [13]. Mazingue et al. [14] reported that the interaction between the target gas and the sensing material led to a change in its refractive...