The development of a completely imperceptible e-skin that enables health monitoring in everyday life can be highly impactful in both societal and economic aspects. One of the most important concerns in modern society is “universal health coverage”. People with very limited access to medical services due to any reason like affordability or physical distance may experience severe health symptoms that could not have occurred if they had access to the medical services promptly. Not only in-time medical treatment but high-tech medical equipment that is located in certain designated regions is available to very limited people. If commercially available e-skin with desired functionalities and reasonable price is provided, such unbalanced medical services can be alleviated through individual self-evaluation of health status using e-skin. Also, this widespread supply of e-skin to the general population can eventually reduce unnecessary social costs that result from delayed medical treatments.
For piezoelectric material, single-crystalline GaN thin film prepared by remote epitaxy is exfoliated and transferred using the 2D material-based layer transfer method. On transferred GaN film, interdigitated electrodes (IDEs) are deposited using conventional photolithography and sputter/e-beam deposition. We have already verified this device structure works well and wireless measurement of health information from the human body could be demonstrated. Our device concept is extremely novel compared to previous studies and demonstrates more comfortable wearing of e-skin with complete imperception.