Ultrasensitive Perovskite Photodetector Achieved When Configured with a Si Metal Oxide Semiconductor Field-Effect Transistor

A novel photodetecting device architecture that combines the optoelectronic property advantages of a perovskite and the amplification properties of a Si metal-oxide-semiconductor field-effect transistor (MOSFET) to innovate a photodetecting system with ultrahigh sensitivity, especially in low-light intensity, is demonstrated. This perovskite-based MOSFET photodetector (PM-PD) can respond as low as 116 nW cm(-2) with extremely high responsivity 4200 A W-1. The perovskite is part of the gate dielectric to modulate the MOSFET drain current when the light intensity is changed. A direct bandgap, organic-inorganic hybrid halide perovskite with a large optical absorption coefficient, can enhance photodetector performance. However, perovskite materials are not good conductors for transporting photogenerated electrons and holes compared with single-crystal silicon. Therefore, the perovskite was utilized as a dielectric where the capacitance is used instead. In the proposed PM-PD architecture, changing the width-to-length (W/L) ratio of perovskite capacitor electrodes, can modulate the dark current from picoamperes to microamperes providing a tunable parameter for optimizing photodetecting performance. Furthermore, the capacitance of the perovskite can be modulated by frequency, which facilitates matching the capacitance of perovskite and MOSFET gate oxide-another important requirement for optimal photodetecting performance. Finally, our novel PM-PD is commensurate with potential 3D monolithic integration.