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Title: Nature of exciton transitions in hexagonal boron nitride

In contrast to other III-nitride semiconductors GaN and AlN, the intrinsic (or free) exciton transition in hexagonal boron nitride ( h-BN) consists of rather complex fine spectral features (resolved into six sharp emission peaks) and the origin of which is still unclear. In this work, the free exciton transition (FX) in h-BN bulk crystals synthesized by a solution method at atmospheric pressure has been probed by deep UV time-resolved photoluminescence (PL) spectroscopy. Based on the separations between the energy peak positions of the FX emission lines, the identical PL decay kinetics among different FX emission lines, and the known phonon modes in h-BN, we suggest that there is only one principal emission line corresponding to the direct intrinsic FX transition in h-BN, whereas all other fine features are a result of phonon-assisted transitions. The identified phonon modes are all associated with the center of the Brillouin zone. Our results offer a simple picture for the understanding of the fundamental exciton transitions in h-BN.
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  1. Texas Tech Univ., Lubbock, TX (United States). Dept. of Electrical and Computer Engineering
  2. Kansas State Univ., Manhattan, KS (United States). Dept. of Chemical Engineering
Publication Date:
Grant/Contract Number:
FG02-09ER46552; 2011-DN-077-ARI048; ECCS-1402886
Accepted Manuscript
Journal Name:
Applied Physics Letters
Additional Journal Information:
Journal Volume: 108; Journal Issue: 12; Journal ID: ISSN 0003-6951
American Institute of Physics (AIP)
Research Org:
Texas Tech Univ., Lubbock, TX (United States)
Sponsoring Org:
USDOE; USDHS Academic Research Initiative (ARI); National Science Foundation (NSF); AT&T Foundation
Country of Publication:
United States
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; time-resolved photoluminescence; semiconductors; band gap; transition metals; nitrides; photoluminescence spectroscopy; excitons; phonons; crystalline solids; crystal structure
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1242863