Flexible gallium oxide electronics

Flexible Ga2O3 devices are becoming increasingly important in the world of electronic products due to their unique properties. As a semiconductor, Ga2O3 has a much higher bandgap, breakdown electric field, and dielectric constant than silicon, making it a great choice for next-generation semiconductor materials. In addition, Ga2O3 is a particularly robust material that can withstand a wide range of temperatures and pressure levels, thus is ideal for harsh environments such as space or extreme temperatures. Finally, its superior electron transport properties enable higher levels of electrical switching speed than traditional semiconducting materials. Endowing Ga2O3-based devices with good mechanical robustness and flexibility is crucial to make them suitable for use in applications such as wearable electronics, implantable electronics, and automotive electronics. However, as a typical ceramic material, Ga2O3 is intrinsically brittle and requires high temperatures for its crystallization. Therefore fabricating flexible Ga2O3 devices is not a straightforward task by directly utilizing the commonly used polymer substrates. In this context, in recent years people have developed several fabrication routes, which are the transfer route, in situ room-temperature amorphous route, and in situ high-temperature epitaxy route. In this review, we discuss the advantages and limitations of each technique and evaluate the opportunities for and challenges in realizing the applications of flexible Ga2O3 devices.