Efficacy of Ion Implantation in Zinc Oxide for Optoelectronic Applications: A Review

Abstract

Unlike the majority of the silicon-based electronic devices, optoelectronic devices are predominantly made using III–V and II–VI semiconductor compounds and their alloys because of their direct bandgap. Among these, zinc oxide (ZnO) is a multifunctional wide bandgap II–VI semiconductor material that has distinctive properties, such as large excitonic binding energy, high-sensitivity, nontoxicity, and good compatibility, which favors it to be considered for various optoelectronic applications including photoelectrochemical (PEC) water splitting, light-emitting diodes (LEDs), photovoltaics, and photodetectors. Though the research concentrated on ZnO started many decades ago, the renewed interest is rekindled only with the availability of high-quality single-crystal substrates, easy growth techniques of various nanostructures, and reports on p-type ZnO. Therefore, ZnO is being treated as a concentrated research focus during the last two decades by researchers encompassing a vast field starting from luminescent materials, energy storage and conversion, to biomedical sensors, and so on. Ion beam irradiation is a fruitful approach to modify the properties of semiconducting oxides by introducing not only impurities but also defects, strains, structural transitions, and others. The necessity of a timely in-depth and critical review of the progress on ion implantation in ZnO is the origin of this Review, which focuses on the recent implantation efforts in nanostructured ZnO thin films as well as single crystals. In the beginning, with an introduction to the general principles of ion implantation, this Review presents interactions and distribution of implantation-induced defects in ZnO. Next, comprehensive analyses on the influence of ion implantation on the optical, electrical properties, and optoelectronic applications including PEC water splitting and LEDs have been revealed. Most importantly, in each section from a “state-of-the-art” of the domain, some critical connections have been provided between the results of the theoretical simulations of the implanted ion-induced defects and the reported data, which in particular would be able to offer significant insights for both theoretical and experimental research community working with the oxide semiconductors. At the end, a summary with future directions for utilizing ion implantation for achieving ZnO thin-film-based high-performance devices has been presented. By including a sufficient breadth and depth of literature coverage in this Review, we believe that it would also tend to reveal the inconsistencies in the extant body of research.