Gas Sensing Using Group IIIA Elements Doped ZnO Thin Films: A Review

Abstract The emission of industrial and automobile toxicants jeopardizes health of human and safety of the environment. The sensitive detection of these toxicants is the priority of the current technological world. Mainly, the metal oxide is used to sense the toxic gases. Out of various metal oxides, ZnO is a promising sensor element and its sensing performance is boosted by using dopants, particularly, group III‐A elements. In the present review, we have focused on the use of group III‐A elements such as boron (B), aluminium (Al), gallium (Ga), indium (In) and thallium (Th) as a doping element in the ZnO matrix to improve its performance and enhance the sensitivity. Meanwhile, the group III‐A elements were never observed in a pure state. However, during the revolution of the modern chemistry, researcher found a way to isolate them. The doping of III‐A element in the ZnO matrix contribute to increases the defects, conductivity of the material, grain size, and crystallinity. In addition, the III‐A element dopant not only increases carrier concentration, but they modify the surface morphology of the host. The review covers the effect of the dopant element on the sensing parameters of ZnO and the sensing mechanism in details.