Wafer‐Scale Fabrication of 2D β‐In₂Se₃ Photodetectors

Abstract 2D materials are considered the future of electronics and photonics, stimulated by their remarkable performance. Among the 2D materials family, β‐In₂Se₃ shows good mobility, excellent photoresponsivity, and exotic ferroelectricity, making it suitable for a wide variety of applications. To date, most reported devices from 2D materials in general, and β‐In₂Se₃ in specific, rely on cumbersome fabrication methods using mechanical exfoliation and transfer of layers onto other substrates. However, for a successful adoption of 2D materials in industry, reliable and reproducible large‐area growth of 2D materials is required. Here, the wafer‐scale epitaxial growth of 2D β‐In₂Se₃ on c‐sapphire using molecular beam epitaxy is demonstrated. Excellent materials quality of thick (90 nm) and very thin films, down to two quintuple layers (2 nm) is confirmed. Furthermore, the fabrication of hundreds of photodetector devices on a 2 in. wafer, using five quintuple layers of β‐In₂Se₃, is demonstrated. They are sensitive to near‐infrared light up to 898 nm wavelength and show a response time of ≈7 ms, which is faster than any result previously reported for β‐In₂Se₃ photodetectors. The devices are produced using photolithography and other standard semiconductor processing methods, which allows easy integration into the current Si technology.