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Title: Acoustic phonon assisted free-carrier optical absorption in an n-type monolayer MoS{sub 2} and other transition-metal dichalcogenides

The theory of free-carrier absorption (FCA) is given for monolayers of transition-metal dichalcogenides, particularly for molybdenum disulphide (MoS{sub 2}), when carriers are scattered by phonons. Explicit expressions for the absorption coefficient α are obtained and discussed for acoustic phonon scattering via screened deformation potential and piezoelectric coupling taking polarization of the radiation in the plane of the layer. It is found that α monotonously decreases with the increasing photon frequency Ω, increases with the increasing temperature T, and linearly depends on two-dimensional electron concentration n{sub s}. Effect of screening, which is ignored in all the earlier FCA studies, is found to reduce α significantly, attributing to the larger effective mass of the electrons. Results are also obtained in the classical and quantum limit giving the power laws α ∼ Ω{sup −2} and T. Comparison of the results is made with those in bulk semiconductors and semiconductor quantum wells.
Authors:
; ;  [1]
  1. Department of Physics, Karnatak University, Dharwad 580 003, Karnataka (India)
Publication Date:
OSTI Identifier:
22494654
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 4; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ABSORPTION; ABUNDANCE; CARRIERS; DEFORMATION; EFFECTIVE MASS; ELECTRONS; MOLYBDENUM SULFIDES; N-TYPE CONDUCTORS; PHONONS; PHOTONS; PIEZOELECTRICITY; POLARIZATION; QUANTUM WELLS; SCATTERING