Al Doped ZnO Thin Films: Beginning to Developments Afoot

In the last three decades, Zinc oxide (ZnO) has been found to be one of the most resourceful materials having tremendous potential applications in manifolds covering a wide variety of areas. It is continuously explored in different forms and structures. ZnO-based layers have an established place in the industry that ranges from protecting degradable items to detecting toxic gases. A wide variety of ZnO-based advanced coatings and their surface treatments along with innovative functionalization technologies offer a multitude of options for making them useful in diverse industries. Multiple techniques ranging from exceedingly sophisticated ones like molecular beam epitaxy and atomic layer deposition to highly-cost effective ones like sol-gel spin coating and dip coating, etc. have been used for developing the ZnO based thin films. Doping suitable elements into ZnO matrix is the most promising strategy to alter its properties drastically. Out of numerous dopants, Aluminum (Al) offers some of the excellent and reproducible features in ZnO films which make Al doped ZnO (AZO) a reputable system in industries like thin film transistor manufacturing and solar cells. Specifically, its established and repeatable behavior in terms of transparency and conductivity becauseis finding huge applications as a transparent conducting oxide (TCO). Extensive research on AZO coatings derived from different methods day-b-day opens up a new gateway for interesting perspectives by optimizing surface nanostructures. Here a brief account of historical developments of ZnO to AZO films along with their applications in certain key areas like TCOs, solar cells, thin film transistors, flexible electronics and plasmonics, etc. is presented.