Narrow bandgap oxide nanoparticles coupled with graphene for high performance mid-infrared photodetection

Abstract

The pursuit of optoelectronic devices operating in the mid-infrared regime is driven by both fundamental interests and envisioned applications ranging from imaging, sensing to communications. Despite continued achievements in traditional semiconductors, notorious obstacles such as the complicated growth processes and cryogenic operation preclude the usage of infrared detectors. As an alternative path towards high-performance photodetectors, hybrid semiconductor/graphene structures have been intensively explored. However, the operation bandwidth of such photodetectors has been limited to visible and near-infrared regimes. Here we demonstrate a mid-infrared hybrid photodetector enabled by coupling graphene with a narrow bandgap semiconductor, Ti2O3 (Eg = 0.09 eV), which achieves a high responsivity of 300 A W−1 in a broadband wavelength range up to 10 µm. The obtained responsivity is about two orders of magnitude higher than that of the commercial mid-infrared photodetectors. Our work opens a route towards achieving high-performance optoelectronics operating in the mid-infrared regime.

Single‐Crystal Hybrid Perovskite Platelets on Graphene: A Mixed‐Dimensional Van Der Waals Heterostructure with Strong Interface Coupling

“…Raman shifts of graphene with and without the growth of MAPbBr 3 platelets were recorded at three different locations to exclude the influence of any inhomogeneity. As reported in previous studies, the G band and 2D band of single‐layer graphene are located at around 1580 and 2700 cm −1 , respectively 33,34. As shown in Figure 3b, the G band appears at 1582.8 and 1595.7 cm −1 for graphene and MAPbBr 3 ‐covered graphene, respectively.…”

“…Since G and 2D band positions are sensitively dependent on the carrier concentration, they can be used to probe the graphene doping level 33–37. Clearly, compared to the uncovered graphene, the covered one displays blue‐shifted G and 2D bands.…”

Two‐dimensional heterostructure promoted infrared photodetection devices

“…The newly developed excitonic species with bions or trions would perhaps be inspiring for ultrafast and ultrasensitive charge transfer. Second, new 2D materials/family with ultranarrow bandgaps with high optical absorption are urgent to be discovered Complementally, exploring the optimal modification of the energy band and electronic properties in existing 2D family is essential.…”

“…C, Band alignment tuning and charge transfer route between graphene and Ti 2 O 3 nanoparticle, responsivity from 4.5 to 10 μm. Reproduced with permission . Copyright 2018, Nature Publishing Group.…”

“…To achieve a broad IR photodetection effectively, Yu et al employed narrow bandgap Ti 2 O 3 ( E g = 0.09 eV) nanoparticles as long‐wavelength optical absorbers, and graphene to provide a fast charge transfer for the photodetectors, a high responsivity of 300 A W −1 and detectable wavelength up to 10 μm were achieved (Figure C). The authors controlled the gate bias therefore modulate the Fermi level of graphene and tune the band misalignment between the graphene and Ti 2 O 3 to tune efficiency of charge transfer.…”