Few-layer Tellurium: one-dimensional-like layered elementary semiconductor with striking physical properties

• 来源期刊: 科学通报（英文版）
• 年，卷（期）: 2018,（3）
• 页码范围: 159-168
• 页数: 10页
• 语种: 英文

摘要

Few-layer Tellurium,an elementary semiconductor,succeeds most of striking physical properties that black phosphorus (BP) offers and could be feasibly synthesized by simple solution-based methods.It is comprised of non-covalently bound parallel Te chains,among which covalent-like feature appears.This feature is,we believe,another demonstration of the previously found covalent-like quasi-bonding (CLQB) where wavefunction hybridization does occur.The strength of this inter-chain CLQB is comparable with that of intra-chain covalent bonding,leading to closed stability of several Te allotropes.It also introduces a tunable bandgap varying from nearly direct 0.31 eV (bulk) to indirect 1.17 eV (2L) and four (two) complex,highly anisotropic and layer-dependent hole (electron) pockets in the first Brillouin zone.It also exhibits an extraordinarily high hole mobility (～ 105 cm2/Vs) and strong optical absorption along the non-covalently bound direction,nearly isotropic and layer-dependent optical properties,large ideal strength over 20％,better environmental stability than BP and unusual crossover of force constants for interlayer shear and breathing modes.All these results manifest that the few-layer Te is an extraordinary-high-mobility,high optical absorption,intrinsic-anisotropy,low-cost-fabrication,tunable bandgap,better environmental stability and nearly direct bandgap semiconductor.This "one-dimen sion-like" few-layer Te,together with other geometrically similar layered materials,may promote the emergence of a new family of layered materials.