Binary Multifunctional Ultrabroadband Self‐Powered g‐C₃N₄/Si Heterojunction High‐Performance Photodetector

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 a multifunctional self‐powered high‐speed ultrabroadband (250–1650 nm) photodetector is reported based on graphitic carbon‐nitride (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 × 105 under 680 nm (49 µW cm−2) illumination. The device also shows an ultrasensitive behavior over the entire operating range at low light illuminations, with highest responsivity (1.2 A W−1), detectivity (2.8 × 1014 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 the device is attributed to the heterojunctions formed by the ultrathin g‐C3N4 nanosheets embedded in the Si surface.

Low‐dimensional nanomaterial/Si heterostructure‐based photodetectors

“…In addition to graphene and TMDs, other materials are also receiving attention due to their unique characteristics. Transition metal carbides or nitrides (MXenes) are also particularly attractive as new 2D materials with tunable work function . Gao and coworkers fabricated self‐driven photodetectors based on vertical Ti 3 C 2 T X /n‐Si heterostructures .…”

“…Transition metal carbides or nitrides (MXenes) are also particularly attractive as new 2D materials with tunable work function. [86][87][88][89][90] Gao and coworkers fabricated self-driven photodetectors based on vertical Ti 3 C 2 T X /n-Si heterostructures. 88 As shown in Figure 5A-F, the thickness of Ti 3 C 2 T x played a critical role in the performance of the photodetector.…”

“…Khanna et al reported an ultrabroadband device based on a g‐C 3 N 4 /Si hybrid 2D/3D heterojunction that exhibited a high on–off ratio of 1.2 × 10 5 under 680 nm illumination, with the detectivity of 2.9 × 10 13 Jones . Its good binary response over the wide spectral range of 250 to 1350 nm suggests that it can be useful in light‐based binary communications and weak signal detection.…”

Harnessing the Potential of Graphitic Carbon Nitride for Optoelectronic Applications

“…This table shows that although g-CN is an excellent material for simple, low-cost, and flexible devices, more effort is required to improve the performance of g-CN photodetectors. In this regard, the photodetector based on a g-CN/Si hybrid 2D/3D structure demonstrated the best overall performance, [148] featuring a broadband photoresponse (250-1650 nm), high responsivity (>50 mA W −1 ), excellent detectivity (>10 13 Jones), large on/off ratio (>10 4 ), and a low response time (<0.4 ms). The best performance (responsivity = 1.2 A W −1 , detectivity = 2.9 × 10 14 Jones) was observed under low light intensity (2 µW cm −2 ) and corresponded to an EQE of 213%.…”

Efficient Charge Separation in Polypyrrole/GaN‐Nanorod‐Based Hybrid Heterojunctions for High‐Performance Self‐Powered UV Photodetection

“…The excellent photoresponse characteristics of the hybrid device were further evaluated using key parameters, such as photocurrent ( I ph ), detectivity ( D* ), responsivity ( R λ ), and external quantum efficiency (EQE) (%), [ 4,14,16–19 ] which are expressed as follows.where Δ I is the difference between photocurrent and dark current. I p , I d , A , P , h , e , and λ are the photocurrent, dark current, device area, power density, Planck's constant, electron charge, and wavelength, respectively.…”