Surface Adsorption and Vacancy in Tuning the Properties of Tellurene

Abstract

The emerging two-dimensional tellurene has been demonstrated to be a promising candidate for photoelectronic devices. However, there is a lack of comprehensive insight into the effects of vacancies and common adsorbates (i.e., O 2 and H 2 O) in ambient conditions, which play a crucial role in semiconducting devices. In this work, with the aid of firstprinciples calculations, we demonstrate that H 2 O and O 2 molecules behave qualitatively differently on tellurene, while water adsorption can be remarkably promoted by adjacent preadsorbed O 2 . Upon the formation of Te vacancies, the adsorption of both O 2 and H 2 O molecules is enhanced. More importantly, the existence of H 2 O and Te vacancies can dramatically facilitate the dissociation of O 2 , suggesting that tellurene may be readily oxidized in humid conditions. In addition, it is found that the electronic properties of tellurene are well preserved upon either H 2 O or O 2 adsorption on the surface. In sharp contrast, vacancies enable significant modification on the band structure. Specifically, an indirect-to-direct band gap transition is found at a vacancy concentration of 5.3%.

Epitaxial Synthesis of Highly Oriented 2D Janus Rashba Semiconductor BiTeCl and BiTeBr Layers

“…Measurement at 0 h refers to Raman spectra collected immediately after the conversion process and samples were kept in ambient conditions (air and 20 °C) for a prolonged amount of time up to 60 h. In the first 24 h time frame, the Raman spectra had shown no noticeable changes but started to broaden and produce weaker signals beyond 24 h. This can be attributed to an increased number of defects in the material and deviation from Γ = 0 Raman condition whether the defect originates from oxidization or the material degradation process. Prior studies have also shown similar degradation effects on other Te based material systems including GaTe, ZrTe 3 , 26,27 tellurene, 28,29 and others. 30,31 These researches show that, reaction with O 2 and H 2 O can be detrimental to tellurium-based thin films.…”

Ab-initio investigation of preferential triangular self-formation of oxide heterostructures of monolayer $$\hbox {WSe}_{2}$$

“…As can be seen, the systems with different sizes of triangular oxide islands show a band gap of 1.6–1.8 eV. The consideration of hybrid functionals can produce a more accurate band gap than the GGA-PBE level of calculation that is known to underestimate the same 49 . Therefore, it is expected that these systems with triangular oxide islands will show optical absorption in the visible spectrum with possible light-harvesting applications.…”

Controlling the Pd Metal Contact Polarity to Trigonal Tellurium by Atomic Hydrogen‐Removal of the Native Tellurium Oxide

“…Theory predicts, and experiment demonstrates, superior contact performance to t‐Te is achievable in the edge contact configuration (i.e., metal atoms are covalently bound to the terminal Te atoms of each 1D Te chain). [ 48,49 ] It is likely that the dangling bonds at the t‐Te chain ends are more reactive than the vdW surfaces of the helical Te chains, [ 14 ] but the relationship between Te domain orientation and reactivity has not yet been studied. It is possible that the oxidation only occurs at Te chain terminations, which would rationalize the formation of the palladium telluride intermetallic even on a Te film with an effective oxide thickness of 1.5 nm.…”

“…Unfortunately, the spontaneous formation of a native oxide on Te in air [ 13,14 ] and the low melting (vaporization) temperature of Te in ambient conditions (in vacuum) [ 15 ] represent difficult‐to‐accommodate engineering challenges. A monumental effort that began early in the development of semiconductor technology dedicated to controlling the chemical and structural properties of the native oxide(s) in all technologically relevant semiconductors (silicon and its analogs, [ 16–19 ] III–V, [ 20–22 ] and 2D material [ 23–26 ] ) continues today and should be extended to novel materials, such as Te.…”