Group‐III Sesquioxides: Growth, Physical Properties and Devices

The group‐III sesquioxides possess material properties that render them interesting for applications such as high‐power rectifiers and transistors, solar‐blind UV detectors and inter‐sub‐band infrared detectors. Technology for growing large, single‐crystalline bulk material and for wafer fabrication exists, enabling homoepitaxial growth of thin films with high crystalline quality. The bandgap can be tuned in an energy range from about 4 to 8 eV for the ternary alloys and allows growth of heterostructures with large band offset. Here, past results and recent investigations on the growth, the material properties, contact fabrication and the alloying of group‐III sesquioxides are reviewed, and an overview on demonstrator devices is provided. Group‐III sesquioxides find potential applications in, for example, deep‐UV photodetectors or power electronics. In this Review, early and current results on the growth and the material properties of binary semiconducting In2O3 and Ga2O3 are discussed, as well as results on the ternary alloys (In,Ga)2O3 and (Al,Ga)2O3. Recent progress in the fabrication of devices is also summarized.