Broadband, High‐Sensitivity Graphene Photodetector Based on Ferroelectric Polarization of Lithium Niobate

Abstract

2D graphene has attracted extensive attention as a promising candidate for high‐performance photodetectors because of its superior optoelectronic properties. However, the realization of high‐sensitivity broadband graphene photodetectors remains a challenge. Lithium niobate (LiNbO3) has the advantages of spontaneous polarization, high dielectric constant, and high voltage electric coefficient, and it can improve the photoelectric detection characteristics of graphene by polarized doping. In this work, n‐ and p‐doping of graphene is demonstrated at the same time with the help of local ferroelectric polarization of x‐cut LiNbO3. This high‐sensitivity and broadband p–n junction photodetector shows a wide detection range of 405 to 2000 nm, a responsivity of ≈2.92 × 106 A W−1 at an incident power of 24 pW (λ = 1064 nm), and a high detectivity of ≈8.65 × 1014 Jones. In particular, a fast rise/decay time of ≈23 ms/≈23 ms is achieved. The graphene‐based LiNbO3 (bulk) photodetector shows higher responsivity​, and the graphene‐based LiNbO3 (film) photodetector a faster response time. This work not only deepens and expands the basic research on 2D materials and ferroelectric materials, but also demonstrates the great potential of doped graphene materials for high‐performance photodetection.

Dynamic and Active THz Graphene Metamaterial Devices

“…Meanwhile, the results showed that the band arrangement of layered heterostructures can be controlled by lattice engineering of 2D nanosheets to improve the photoelectric properties. Similarly, Guan et al showed that heterojunction formation by doping graphene could improve the light-detection capability of detections in their device based on ferroelectric polarization of L i NbO 3 [108]. The detectors' performance, such as detectivity and responsivity, improved by several orders of magnitude compared to previously reported devices.…”

Advances in lithium niobate photonics: development status and perspectives

“…2, LN has a strong pyroelectric coefficient, which is suitable for the fabrication of a pyroelectric PD. 48,336 As the pyroelectrical current is inversely proportional to the dielectric thickness, 337 a thinner LN thickness is preferred in such devices. 338 However, in the typical bulk LN platform, it is challenging to reduce the LN thickness down to several micrometers, 339 whereas this will be quite easy when transferring this technology to the TFLN platform.…”

“…More recently, Guan et al combined the pyroelectric effect of X-cut LN with graphene and realized a broadband (405 to 2000 nm) and high detectivity (∼8.65 × 10 14 Jones) graphene PD. 336 Compared with other pyroelectric material platforms, the high pyroelectrical coefficient feature of LN will continually get attention, especially for some applications such as gas sensing.…”

Graphene/Quantum Dot Heterostructure Photodetectors: From Material to Performance

“…[60] The graphene/carbon QD heterostructure photodetectors also show an ultrashort rise time of 0.93 µs and a fall time of 2.24 µs (Figure 3e,f), which is much faster than the response time of graphene photodetectors (in the level of s or ms). [61] With the strong response to UV light, SnSe 2 QDs have also been hybridized with graphene into graphene/SnSe 2 QD heterostructure photodetectors, [30] which shows an R of 7.5 × 10 3 AW −1 with a rise time of 0.31 s and a fall time of 1.3 s (corresponding to UV light, λ = 405 nm). Graphene/ZnO QD heterostructure photodetector shows a high R of 247 AW −1 (corresponding to UV, λ = 325 nm) with a response time of ms. [27] The introduction of graphene/QD heterostructures can also boost the performance of visible photodetectors.…”