Enhanced linear dynamic range and response speed in interdigital-electrode solar-blind photodetector by contact engineering

Abstract

As an ultra-wide bandgap semiconductor, gallium oxide (Ga2O3) has great market potential in the field of solar-blind UV photodetectors. However, the slow response time of hundreds of milliseconds has seriously hindered the commercialization of the Ga2O3 photodetector. Here, we design an interdigital-electrode solar-blind UV β-Ga2O3 photodetector by using high-work function metal Pd as contacts. The atomic transmission electron microscopy data reveal that the Pd-Ga2O3 interface is clean and smooth, composed of a Ga2O3 single crystal and a local Pd single crystal, beneficial for weakening Fermi-level pinning. A low-damage and low-defect contact interface provides an excellent photoelectric response time of 2.4 ms (rise)/2.6 ms (descend) and a large linear dynamic range of 140 dB. On a 2-in. wafer of β-Ga2O3 film, we made a 12 × 12 array in which all 64 (8 × 8) devices tested maintained consistent performance and high reliability. Our high-performance Pd-Ga2O3 interdigital-electrode solar-blind photodetectors provide assurance for UV communication and imaging applications.