Van der Waals Epitaxy and Photoresponse of Hexagonal Tellurium Nanoplates on Flexible Mica Sheets

Abstract

Van der Waals epitaxy (vdWE) is of great interest due to its extensive applications in the synthesis of ultrathin two-dimensional (2D) layered materials. However, vdWE of nonlayered functional materials is still not very well documented. Here, although tellurium has a strong tendency to grow into one-dimensional nanoarchitecture due to its chain-like structure, we successfully realize 2D hexagonal tellurium nanoplates on flexible mica sheets via vdWE. Chemically inert mica surface is found to be crucial for the lateral growth of hexagonal tellurium nanoplates since it (1) facilitates the migration of tellurium adatoms along mica surface and (2) allows a large lattice mismatch. Furthermore, 2D tellurium hexagonal nanoplates-based photodetectors are in situ fabricated on flexible mica sheets. Efficient photoresponse is obtained even after bending the device for 100 times, indicating 2D tellurium hexagonal nanoplates-based photodetectors on mica sheets have a great application potential in flexible and wearable optoelectronic devices. We believe the fundamental understanding of vdWE effect on the growth of 2D tellurium hexagonal nanoplate can pave the way toward leveraging vdWE as a useful channel to realize the 2D geometry of other nonlayered materials.

Te hexagonal nanotubes: formation and optical properties

“…6b. The similar high-energy light emission in Te nanostructures have also been found by the other researchers, such as in nanobelts and nanochains [25,26]. The PL peak has been ascribed to the electron radiation transition from p-antibonding triple of conduction band (CB) to p-bonding triple of valence band (VB), and four deconvoluted peaks are found at 334, 397, 460, and 507 nm, which indicate the difference originating mechanism to ours.…”

“…The Te hexagonal tubular nanostructure has strong Raman active phonon modes. The peak at 118 cm -1 is related to the A 1 mode, corresponding to the atoms moving in the basal plane [25,40]. Peaks at 90 and 140 cm -1 both belong to the degenerate E modes, which can be specifically ascribed to the a-/b-axis rotations and c-axis asymmetric stretching, respectively.…”

“…The first report on PL property of Te nanostructure so far as we know indicates strong peaks at about 410, 433, and 452 nm [18]. After that, great interest and discussion have been given on the blue-violet PL of Te nanostructures due to their strong application back ground as optoelectric devices [19][20][21][22][23][24][25]. To the best of our knowledge, only the works by Wang et al [25] and Lin et al [26] have discussed on the origination mechanism of the PL.…”

“…After that, great interest and discussion have been given on the blue-violet PL of Te nanostructures due to their strong application back ground as optoelectric devices [19][20][21][22][23][24][25]. To the best of our knowledge, only the works by Wang et al [25] and Lin et al [26] have discussed on the origination mechanism of the PL. The most important contradiction of this material to the traditional semiconductor is that the PL peak always lies in the visible range (usually from 2.2 to 3.1 eV), which is higher than the bandgap of Te (0.3 eV).…”

Multivalency-Driven Formation of Te-Based Monolayer Materials: A Combined First-Principles and Experimental study

“…To date, the existing 2D materials can be divided into two categories: one that can be mechanically exfoliated from its layered bulk counterpart, such as graphene and MoS 2 ; the other, acking a layered bulk counterpart, has to be grown epitaxially on a proper substrate, such as silicene and stanene. Meanwhile, the Te-I bulk has the form of helical chains along the c axis, and the Te films most easily grow in the [001] direction [21], totally different from the structure of tellurene. Surprisingly, the monolayer or multilayers of tellurene can be generated via the new formation mechanism characterized by a thickness-dependent structural phase transition in the ultrathin film regime, as discussed below.…”