1D Germanium Sulfide van der Waals Bicrystals by Vapor–Liquid–Solid Growth

Abstract

Defects in two-dimensional and layered materials have attracted interest for realizing properties different from those of perfect crystals. Even stronger links between defect formation, fast growth, and emerging functionality can be found in nanostructures of van der Waals crystals, but only a few prevalent morphologies and defect-controlled synthesis processes have been identified. Here, we show that in vapor–liquid–solid growth of 1D van der Waals nanostructures, the catalyst controls the selection of the predominant (fast-growing) morphologies. Growth of layered GeS over Bi catalysts leads to two coexisting nanostructure types: chiral nanowires carrying axial screw dislocations and bicrystal nanoribbons where a central twin plane facilitates rapid growth. While Au catalysts produce exclusively dislocated nanowires, their modification with an additive triggers a switch to twinned bicrystal ribbons. Nanoscale spectroscopy shows that, while supporting fast growth, the twin defects in the distinctive layered bicrystals are electronically benign and free of nonradiative recombination centers.

Phase-Specific Vapor–Liquid–Solid Growth of GeSe and GeSe2 van der Waals Nanoribbons and Formation of GeSe–GeSe2 Heterostructures

“…The incident electron beam current for CL measurements was typically 400 pA at an integration time of 10 s per spectrum. CL spectra were obtained on as-grown and selenized GeSe ribbons with identical thickness, determined by measuring the attenuation of the electron beam current in HAADF-STEM …”

“…CL spectra were obtained on as-grown and selenized GeSe ribbons with identical thickness, determined by measuring the attenuation of the electron beam current in HAADF-STEM. 44 ■ ASSOCIATED CONTENT * sı Supporting Information…”

Emerging Nonplanar van der Waals Nanoarchitectures from 2D Allotropes for Optoelectronics

“…[22,[138][139][140] Vapor-liquid-solid (VLS) growth method is a well-known anisotropic growth strategy, and all the vdW spiral nanowires reported so far have been prepared in this way. [138,22,[139][140][141][142][143][144][145] Metal nanoparticles (Au, Ag, Bi, etc.) are provided as the catalyst to form low-melting point eutectic alloys and also serve as the seeds and transport media for growth.…”

“…are provided as the catalyst to form low-melting point eutectic alloys and also serve as the seeds and transport media for growth. [140][141][142][145][146][147] Under low pressure (10 −3 -10 1 Torr), the alloy droplet reaches supersaturation due to the entry of gaseous precursor, and subsequent growth occurs at the droplet/nanowire interface. The initial diameter of spiral nanowires is equivalent to the droplet size, which could be adjusted by controlling the concentration and the composition of precursors to tune the twist rate and period length, as the entry of precursor affect the surface tension of the alloy droplet.…”

New Approach to Low-Power-Consumption, High-Performance Photodetectors Enabled by Nanowire Source-Gated Transistors

“…As the one-dimensional nanowires (NWs) of two-dimensional layered crystals, GeS NWs are of particular interest for twistronics from 2019. − Beyond twistronics, it is also meaningful to broaden the photodetection function of GeS NWs, owing to the advantages of high optical absorption coefficient, high carrier mobility, low toxicity, and great stability in an ambient atmosphere. , In this work, the low-power-consumption SGT photodetectors are first demonstrated successfully by utilizing the functional sulfur-rich shelled GeS NWs. The fabricated SGTs show extremely low V SAT (0.61 V ± 0.29 V) that is weakly dependent on the applied V GS (∼0.03) and extremely low power consumption of 7.06 pW.…”