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Updated: Jun 1, 2026

Probe Type II Band Alignment in One-Dimensional Van Der Waals Heterostructures Using First-Principles Calculations
Published on: October 12, 2019
Resolving band-structure evolution and defect-induced states of single conjugated oligomers by scanning tunneling
Shiyong Wang1, Weihua Wang, Nian Lin
1Department of Physics, The Hong Kong University of Science and Technology, Hong Kong, China.
Abstract:
We study single conjugated polyphenylene oligomers consisting of 3n (2 ≤ n ≤ 12) phenyl units by means of cryogenic scanning tunneling microscopy and spectroscopy. The spatially resolved local densities of states reveal a progressive development of a continuous conduction band out of discrete molecular orbitals as the length of the oligomers increases. The experimental results are satisfactorily described by tight-binding calculations which gave a conduction band bandwidth of 4.5 ± 0.2 eV and a band gap of 3.1 ± 0.2 eV for an infinitely long polymer. We observed two types of defects, known as conformational torsional angle misfit and metasite kink. Tight-binding as well as density-functional theory model calculations confirm that both types of defects effectively destroy the delocalization.
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