Self-powered, temperature-sensitive, solar-blind photodetector based on a Pt–ZnGa2O4–Al Schottky junction induced by coupling of photovoltaic and interfacial pyroelectric effects

Abstract

The interfacial pyroelectric effect, induced by polar symmetry at the interface of centrosymmetric materials, has been successfully used to improve the photovoltaic properties of self-powered photodetectors. However, the traditional pyroelectric effect enhanced self-powered photodetectors are almost all based on heterojunction structures, and their lattice mismatch leads to the deterioration of material quality, which obstructs the progress of device performance. In this study, a pyroelectric effect enhanced self-powered Pt–ZnGa₂O₄–Al planar Schottky photodetector has been designed and demonstrated for the first time on a high-quality ZnGa₂O₄ thin film fabricated by metal organic chemical vapor deposition. The full width at half maximum (FWHM) of the (222) rocking curve peak of ZnGa₂O₄ thin film on c-sapphire is as narrow as ∼0.038°. The Pt–ZnGa₂O₄–Al planar Schottky device demonstrates a ∼170% enhancement in responsivity and a more than 10 times improvement in the response speed by the interfacial pyroelectric effect. Moreover, the enhancement of the photoresponse characteristics of the device by the interfacial pyroelectric effect relies heavily on the light intensity, temperature and external bias. In particular, the responsivity of ∼1.36 mA W⁻¹ and rapid rise/fall times less than 40 ms can be observed under 255 nm light illumination over a wide power density range of 50–3300 μW cm⁻² at 0 V bias with an operating temperature of 28 °C. These results open up a new feasible way to use the interfacial pyroelectric effect to regulate the performance of photodetectors.