Phase engineering and optical properties of 2D MoSe 2: Promise and pitfalls

Eve D. Hanson, Laura M. Lilley, Jeffrey D. Cain, Shiqiang Hao, Edgar Palacios, Koray Aydin, Christopher M Wolverton, Thomas J Meade, Vinayak P Dravid*

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

Phase engineering monolayer MoS 2 , selectively controlling the MoS 2 2H to 1T′ transition via lithium intercalation, has driven recent excitement in the nanoscale electronics field, due to resultant MoS 2 contact resistance reduction and the compatibility of MoS 2 with CMOS device architecture. Here, we report the “on-chip” 2H to 1T′ transition for the related MoSe 2 system, which has a smaller 1.55 eV 2H bandgap, and for which the 1T′ phase transformation should be more energetically favorable. We report the first on-chip 2H to 1T′ transformation of monolayer MoSe 2 on both SiO 2 and sapphire substrates. The on-chip 1T′–MoSe 2 shows higher transparency despite an increased number of metallic states, indicating tunable optoelectronic properties with potential applications in transparent electrodes and energy harvesting. We also describe the challenges introduced by on-chip phase engineering via n-butyllithium exposure. Density functional theory (DFT) calculations indicate that Li + ions are required on both sides of the MoSe 2 monolayer to create a strong thermodynamic driving force for the 1T′ transformation. We observe that patterned n-butyllithium exposures can be inconsistent, with widely variable kinetics. Due to manifest n-butyllithium-engineered 1T′ MoSe 2 stability concerns we propose the process is an unreliable processing technique for 2D electronics.

Original languageEnglish (US)
Pages (from-to)219-226
Number of pages8
JournalMaterials Chemistry and Physics
Volume225
DOIs
StatePublished - Mar 1 2019

Keywords

  • 2D materials
  • MoSe
  • Nanomaterials
  • Phase engineering

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics

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