Graphene/silicon Schottky junctions have been proven efficient for photodetection, but the existing high dark current seriously restricts applications such as weak signal detection. In this paper, a thin layer of gadolinium iron garnet (Gd3Fe5O12, GdIG) film is introduced to engineer the interface of a graphene/silicon Schottky photodetector. The novel structure shows a significant decrease in dark current by 54 times at a −2 V bias. It also exhibits high performance in a self-powered mode in terms of an Ilight/Idark ratio up to 8.2 × 106 and a specific detectivity of 1.35 × 1013 Jones at 633 nm, showing appealing potential for weak-light detection. Practical suitability characterizations reveal a broadband absorption covering ultraviolet to near-infrared light and a large linear response with a wide range of light intensities. The device holds an operation speed of 0.15 ms, a stable response for 500 continuous working cycles, and long-term environmental stability after several months. Theoretical analysis shows that the interlayer increases the barrier height and passivates the contact surface so that the dark current is suppressed. This work demonstrates the good capacity of GdIG thin films as interlayer materials and provides a new solution for high-performance photodetectors.

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In this work, the electrical property of Au/graphene oxide/p-InP hetero-structure has been evaluated by I–V and C–V measurements in dark and illuminated conditions (visible light). The diode exhibited significant rectifying behavior, thus indicating the heterojunction-type diode. The key electrical parameters of heterojunction diode including ideality factor (n), series resistance (Rs), shunt resistance (Rsh), and barrier height (Фb) are estimated from I–V data based on the theory of thermionic emission. The modified Norde and Cheung’s methods were utilized to evaluate the electrical parameters and compared the results. The current conduction mechanism at different voltage regions of I–V has also been investigated. The variation of 1/C2 versus voltage signifies linearity at high frequency (1 MHz), indicating that the type of heterojunction can be abrupt. The experimental outcomes of this study revealed that the performance of heterojunction diode in dark is considerably good as compared to the illumination condition with respect to the lower values of Фb, n, Rs, and interface state density (Nss).

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