ABSTRACT

Metal oxide gas sensors (MOGS) are solid-state devices which are extensively used for various applications ranging from medical diagnostics, food processing, recognition of noxious and explosive gases and emission control. These sensors are much compatible with present day automated devices and fascinating because of their simplicity, sensitivity and low cost. Nanomaterials like nanoparticles, nanorods and nanowires have influenced the research emphasis in this field due to their large number of surface sites, and improved enhancements in the selectivity of these materials are essential for their effective implementation. Many recent studies have proven that the selectivity and other important sensing constraints of MOGS can be upgraded over the usage of heterojunction metal oxide based materials. The physical interfaces integrating dissimilar materials are often referred to as heterojunctions. Incorporating two or more metal oxides forming heterojunction interfaces can have drastic effects on gas sensor performance. In recent times, these possessions have been augmented by manipulating heterojunctions in nanoscale. This chapter specifies various morphological curriculums currently available for nanoscale metal-oxide based heterojunction materials and their implementation in gas sensor sector. Further, the modern advances are emphasized and feasible developments have been examined.