MXene–Silicon Van Der Waals Heterostructures for High‐Speed Self‐Driven Photodetectors

Abstract

MXenes, or transition metal carbides or nitrides, as an advanced 2D materials have already attracted extensive attention due to their high conductivity and large specific surface area for applications in the field of energy storage. MXenes also have many other advanced properties such as good transmittance and adjustable work function over a large range. However, few works study the properties of MXenes in the field of optoelectronics. Here, the optoelectronic properties of Ti3C2TX (with a work function of 4.37 eV) on n‐type silicon (n‐Si) of vertical van der Waals heterostructures are studied. The Ti3C2TX not only functions as the transparent electrode but also contributes to the separation and transport of photo‐induced carriers. After investigations on the influence of annealing, temperature, illumination, and applied voltage on the performance of Ti3C2TX/n‐Si Schottky junction heterostructures, this study fabricates a self‐driven vertical junction photodetectors with high response and recovery speeds. It is believed that the excellent photoelectric properties of MXenes will attract many researchers' attention to the application of MXenes in the photoelectrical field.

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 .…”

“…E and F show the schematic illustration of the Ti 3 C 2 T X /n‐Si device with a thin and thick film of Ti 3 C 2 T X . The carriers in the two devices have different behaviors . Copyright 2017, Wiley‐VCH…”

“…The carriers in the two devices have different behaviors. 88 Copyright 2017, Wiley-VCH responsivity of 9 mA W −1 , suggesting its promising application in infrared imaging.…”

“…[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. Thinner films have better transmittance; however, the weak built-in electric field is not conducive to the performance.…”

Beyond Gold: Spin‐Coated Ti3C2‐Based MXene Photodetectors

“…Finally, MXenes, including Ti 3 C 2 T z used here, have the unique attribute that their work function can be adjusted from 2.14 to 5.65 eV by different means, such as hole injection or surface termination using oxygen, fluorine, or chlorine . This provides a wider range compared to all metals used in MSM detectors . Consequently, if the Fermi level is not pinned in the semiconductor, as is the case in silicon, MXenes could be used as ohmic, or Schottky contacts at will, resulting in a range of optoelectronic applications, such as having low noise MSMs with Schottky contacts, or high gain photoconductors with two ohmic contacts.…”