Recent Progress of Rare Earth Oxides for Sensor, Detector, and Electronic Device Applications: A Review

Rare earth oxides (REOs) are deemed important from both industrial implementation and research insight perspectives. One of the most conspicuous attributes of REOs is sensing, which contributes significantly to the development of diversified and robust systems of sensors and detector devices. However, there has not been any organized review that has pointed out critical insights from the sensor, detector, and electronic device perspectives that can invoke further studies to investigate the prospective and commercially relevant areas to date. To address this limitation, this review undertakes a focused report approach. From this concise yet comprehensive review, it has been prominent that the most significant contributions to the sensing and detecting fields by the REOs are in electrochemical, temperature, humidity, radiation, gas, and biosensors. Moreover, in terms of electronic device development, REOs have had a significant impact on memory devices, metal oxide semiconductors, dielectric materials, capacitors, energy storage devices, and so on. Furthermore, one of the key findings of the study is that the REOs have flexible doping (e.g., Er3+, Yb3+, Y3+, etc.) capability combined with other host materials such as HfO2 film, SiO2 stacks, TiO2, SnO2 nanostructures, etc., which will likely make REO-based electrochemical sensor and biosensor development the most promising sector in the coming years. Despite the impressive aspects, biocompatibility issues in several biological and biomedical systems along with the hygroscopic nature of REOs in electronic devices remain as concerns. However, these issues can be addressed by the advancement of intricate technologies such as targeted manipulation of the electronic configuration of REOs, multifarious doping experiments to obtain alternative mechanisms, etc. to obtain superior biocompatibility, and device development systems that are noninvasive to the environment. From the commercialization front, memory devices and energy storage devices will be the focusing points for large-scale investors due to improved mechanical (i.e., Young's modulus, intrinsic stress, etc.) and electrical (i.e., high dielectric constant, resistivity, relative permittivity, etc.) properties, while REO-based metal oxide semiconductor and capacitor development is likely to be research-oriented for the next few years before making the eventual move to futuristic applications at a large industrial scale. In short, this review reports a substantial number of relevant studies that will pave the way for further experimental and computational investigations on REOs and their sensor, detector, and electronic device aspects.