Topological insulator nanostructures for near-infrared transparent flexible electrodes

Abstract

Topological insulators are an intriguing class of materials with an insulating bulk state and gapless Dirac-type edge/surface states. Recent theoretical work predicts that few-layer topological insulators are promising candidates for broadband and high-performance optoelectronic devices due to their spin-momentum-locked massless Dirac edge/surface states, which are topologically protected against all time-reversal-invariant perturbations. Here, we present the first experimental demonstration of near-infrared transparent flexible electrodes based on few-layer topological-insulator Bi(2)Se(3) nanostructures epitaxially grown on mica substrates by means of van der Waals epitaxy. The large, continuous, Bi(2)Se(3)-nanosheet transparent electrodes have single Dirac cone surface states, and exhibit sheet resistances as low as ~330 Ω per square, with a transparency of more than 70% over a wide range of wavelengths. Furthermore, Bi(2)Se(3)-nanosheet transparent electrodes show high chemical and thermal stabilities as well as excellent mechanical durability, which may lead to novel optoelectronic devices with unique properties.

Aharonov–Bohm oscillations in a quasi-ballistic three-dimensional topological insulator nanowire

“…Previous results on similar samples 16 demonstrate that the resistance maximum coincides well with the charge neutrality point, and that the discrepancy, in gate voltage, between these and the Dirac point should be less than 1 V. Nanowires are obtained via mechanical exfoliation of a bulk TI crystal (Bi 1.33 Sb 0.67 )Se 3 onto Si/SiO 2 substrates, where the doped substrate acts as a global backgate (see Methods). While chemical or mechanical etching allows for effective production of nanowires from layered thin films, these processes typically introduce additional damage and defects along the edges 17,18 . We fabricated two four-terminal devices having channel lengths of L 1 ¼ 200 nm and L 2 ¼ 350 nm (see Fig.…”

Bismuth‐based candidates for topological insulators: Chemistry beyond Bi2Te3

“…A more pronounced electronic confinement can be achieved by substituting rhodium for platinum along with subsequent electron-charge compensation by a spacer layer in the structure of [(Bi 4 Rh) 3 [88]. The demonstrated chemical flexibility of the decorated honeycomb-type slab gives strong hopes towards extension of the new TI class by structural design with these slabs and fine chemical tuning by doping.…”

“…The metallic conductivity is retained but yet restricted to the intermetallic framework. The stronger oxidized compound [(Bi 4 Pt) 3 [86] is already a layered 2D metal or a sort of a supra-molecular www.pss-rapid.com status solidi physica rrl quantum well (Fig. 7b).…”

“…In this table, we provide the value for the lattice parameter b instead. 3 A highly demanded single-layer bismuth ultrathin film, or a 1-BL Bi(111) film ( [17,18], cf. Section 2.1), has been grown epitaxially on a Bi 2 Te 3 substrate, thanks to the similarity of the lattice constants a of elemental bismuth and Bi 2 Te 3 .…”

“…For instance, bismuth-chalcogenide TIs have to be tuned by well-controlled doping, and investigations of predicted 3D TIs with nearly cubic structures are hampered by exfoliation failures. Whereas many studies are aiming at nanostructurization of Bi 2 Q 3 , Q = Se, Te (in organic solutions [2], on mica substrates [3]) and tuning it for future applications (synthesis of ultrathin films [4] and heterostructures where quintuple layers of Bi 2 Q 3 are interlaced with insulating slabs [5]), the search for new candidate compounds is also underway. …”