Binary Multifunctional Ultrabroadband Self-Powered g-C3N4 /Si Heterojunction High-Speed Photodetector

TL;DR

This paper introduces a self-powered, ultrabroadband g-C3N4/Si heterojunction photodetector capable of high-speed binary photoswitching across 250-1650 nm, with high responsivity, detectivity, and fast response times, suitable for optical interconnects.

Contribution

The work presents a novel multifunctional ultrabroadband self-powered photodetector based on g-C3N4/Si heterojunctions with binary photoswitching and high-speed operation, filling a gap in existing optical detector technology.

Findings

Achieves high ON/OFF ratio of 1.2 x 10^5 at zero bias.

Demonstrates high responsivity of 1.2 AW-1 and detectivity of 2.8 x 10^14 Jones.

Response times are approximately 0.23 ms for response and 0.60 ms for recovery.

Abstract

Compact optical detectors with fast binary photoswitching over a broad range of wavelength are essential as an interconnect for any light-based parallel, real-time computing. Despite of the tremendous technological advancements yet there is no such single device available that meets the specifications. Here we report a multifunctional self-powered high-speed ultrabroadband (250-1650 nm) photodetector based on g-C3N4/Si hybrid 2D/3D structure. The device shows a novel binary photoswitching (change in current from positive to negative) in response to OFF/ON light illumination at small forward bias (<0.1 V) covering 250-1350 nm. At zero bias, the device displays an extremely high ON/OFF ratio of 1.2 x 10^5 under 680 nm (49 microWcm-2) illumination. The device also shows an ultrasensitive behaviour over the entire operating range at low light illuminations, with highest responsivity (1.2 AW-1), detectivity (2.8 x 10^14 Jones) and external quantum efficiency (213%) at 680 nm. The response and recovery speeds are typically 0.23 and 0.60 ms, respectively, under 288 Hz light switching frequency. Dramatically improved performance of our device is attributed to the heterojunctions formed by the ultrathin g-C3N4 nanosheets embedded in the Si surface.