Growth and Strain Engineering of Trigonal Te for Topological Quantum Phases in Non-Symmorphic Chiral Crystals

Abstract

Strained trigonal Te has been predicted to host Weyl nodes supported by a nonsymmorphic chiral symmetry. Using low-pressure physical vapor deposition, we systematically explored the growth of trigonal Te nanowires with naturally occurring strain caused by curvature of the wires. Raman spectra and high mobility electronic transport attest to the highly crystalline nature of the wires. Comparison of Raman spectra for both straight and curved nanowires indicates a breathing mode that is significantly broader and shifted in frequency for the curved wires. Strain induced by curvature during growth therefore may provide a simple pathway to investigate topological phases in trigonal Te.

A high performance self-powered photodetector based on a 1D Te–2D WS2 mixed-dimensional heterostructure

“…Te microwire shows three vibration peaks locating at 85.6 cm -1 , 115.2 cm -1 and 134.3 cm -1 , which are corresponding to the in-plane E 1 , E 2 and A 1 (out-of-plane) vibrations, respectively [13]. The in-plane E 1 2g and out-of-plane A 1g modes of the multilayered WS 2 nanosheet are observed at 348.1 cm -1 and 418.7 cm -1 , respectively [39]. The Raman spectrum of Te-WS 2 vdWs heterostructure exhibits the combination of phonon modes of both Te wire and WS 2 .…”

“…1c shows the PL of the WS 2 and WS 2 -Te heterostructure with 532 nm laser excitation. In general, the exfoliated multilayered WS 2 nanosheet shows two clear PL peaks at 660nm and 861 nm, corresponding to a red-shifted direct optical band gap of 1.88 eV and an indirect band gap of ~1.44 eV [39]. A PL quenching effect is observed in the overlapped region for both PL peaks, which is ascribed to a strong interlayer coupling effect between Te and WS 2 .…”

“…Noticeably, the large dark current and ultrafast electron-hole recombination rate of Te are the main disadvantages for further application because of the narrow band gap of Te in bulk. Fortunately, as a typical TMDs material, WS 2 shows merits of moderate bandgap (1.4-2.0 eV), high optical quality and broadband light absorption coefficiency, which is an idea candidate in type-II heterostructure based device [39]. In this paper, we demonstrate a mixed-dimensional heterostructure of 1D Te microwire covered by 2D WS 2 nanosheet via the polyvinyl alcohol (PVA) dry transfer method.…”

Novel two-dimensional monoelemental and ternary materials: growth, physics and application

“…However, the thickness of Te is beyond 30 nm and the lateral dimensions are in the range of 6-10 μm [136]. After that, Te nanostructures based on other substrate such as sapphire, graphene/4H-SiC and HOPG have also be studied in recent years [137][138][139][140][141][142][143]. In general, there are many kinds of synthetic methods, including physical vapor deposition (PVD) [135], MBE [138], LPE [144][145][146], hydrothermal reaction [131,132,147,148], CVD [130] and thermal evaporation deposition [149,150].…”

“…Reasonably, the magnetic transport behavior of 2D Te with high mobility is reported and probably brings a novel phenomenon along different directions [131,155]. The TI behavior found in 2D α-Te over the 3-nm region was determined by STM [148], already theoretical explained in strain engineering for Te nanowires and nanosheets [143,154,156]. For optical behavior, 2D Te with a thickness from 9.1 nm to 20.5 nm showed four red-shifted Raman peaks of 94 cm −1 (E 1 TO), 105 cm −1 (E 1 LO), 125 cm −1 (A 1 ) and 143 cm −1 (E 2 ), attributed to the augmentation of deformation potential in lattice orientation and the interlayer long-range Coulombic interactions [130,147].…”