Long-Range Lattice Engineering of MoTe2 by a 2D Electride

• Published in: Nano letters 2017-06, Vol.17 (6), p.3363-3368
• Main Authors: Kim, Sera, Song, Seunghyun, Park, Jongho, Yu, Ho Sung, Cho, Suyeon, Kim, Dohyun, Baik, Jaeyoon, Choe, Duk-Hyun, Chang, K. J, Lee, Young Hee, Kim, Sung Wng, Yang, Heejun
• Format: Article
• Language: English
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/acs.nanolett.6b05199

Doping two-dimensional (2D) semiconductors beyond their degenerate levels provides the opportunity to investigate extreme carrier density-driven superconductivity and phase transition in 2D systems. Chemical functionalization and the ionic gating have achieved the high doping density, but their effective ranges have been limited to ∼1 nm, which restricts the use of highly doped 2D semiconductors. Here, we report on electron diffusion from the 2D electride [Ca2N]+·e– to MoTe2 over a distance of 100 nm from the contact interface, generating an electron doping density higher than 1.6 × 1014 cm–2 and a lattice symmetry change of MoTe2 as a consequence of the extreme doping. The long-range lattice symmetry change, suggesting a length scale surpassing the depletion width of conventional metal–semiconductor junctions, was a consequence of the low work function (2.6 eV) with highly mobile anionic electron layers of [Ca2N]+·e–. The combination of 2D electrides and layered materials yields a novel material design in terms of doping and lattice engineering.