Silicene/Silicene Oxide Nanosheets for Broadband Photodetectors

Abstract

Nanosheets of silicene, a 2D material made of silicon atoms, have great potential for use in next-generation electronic and optoelectronic devices due to their unique properties. However, issues in the large-scale production of silicene nanosheets and in their degradation still present challenges for these applications. Here, we report a method to obtain large quantities of single to fewlayer thick silicene/silicene oxide ("Si nanosheets") from calcium disilicide (CaSi 2 ). We also show that the silicene nanosheets experience oxidation in air and are highly oxidized after 12 weeks of storage. Density functional theory studies were performed and provide a detailed understanding of this oxidation. Silicene/ silicene oxide nanosheet-based photodetector devices were also fabricated for the first time. They show a broadband response in the visible spectral range with outstanding responsivity (14.3 A/W), detectivity (3 × 10 10 Jones), and external quantum efficiency (44.6%), demonstrating the promising applications of this material for optoelectronic devices.

State-of-the-art advancements of atomically thin two-dimensional photocatalysts for energy conversion

“…[10][11][12][13][14] Since Novoselov, Geim, and co-workers demonstrated the isolation of graphene using the famous method of mechanical exfoliation in 2004, 15 ''2D materials,'' especially the atomically layered ones, as a new class of materials, have attracted growing attention. Motivated by the success of graphene, some representative materials emerged and have been also intensively studied, mainly including hexagonal boron nitride (hBN), 16 transition metal dichalcogenides, 17 layered transition oxides, 18 layered double hydroxides (LDHs), 19 black phosphorus (BP), 20 silicene, 21 and germanene. 22 These 2D materials show 2D-limited transport of electrons and phonons, thereby delivering lots of interesting phenomena.…”

Epitaxial Growth of Crystalline CaF2 on Silicene

“…41 The same peak is also observed in silicene layers obtained by removing Ca from CaSi 2 through HCl deintercalation, and it is also assigned to the same vibration of the 2D Si planes. 42,43 The observed polarization dependency and the similarity to the CaSi 2 spectrum strongly suggest that the 388 cm −1 mode is related to the out-of-plane vibration of the Si atoms, with a strong blueshift compared to bare silicene on Ag(111). It is then reasonable to assign the 457 cm −1 vibrational mode to the in-plane vibration of Si atoms: this mode is therefore strongly red-shifted, if compared to the one detected in silicene/Ag(111), 17,36 but blueshifted with respect to the in-plane mode of Si atoms in CaSi 2 structures.…”

Two-Dimensional Quantum-Confined CsPbBr3 in Silicene for LED Applications

“…We have previously produced silicene through an exfoliative process, using CaSi 2 as a starting material. 18 In short, this process consists of the removal of Ca from CaSi 2 using HCl, followed by sonication and centrifugation, after which the silicene are dried and stored in vacuum for use. Figure S1 shows XRD patterns of the starting material, CaSi 2 , and silicene after exfoliation and confirms that silicene layers were indeed obtained.…”

“…We have previously produced silicene through an exfoliative process, using CaSi 2 as a starting material . In short, this process consists of the removal of Ca from CaSi 2 using HCl, followed by sonication and centrifugation, after which the silicene are dried and stored in vacuum for use.…”