title: Nanotwin Detection and Domain Polarity Determination via Optical Second Harmonic Generation Polarimetry.
abstract: We demonstrate that optical second harmonic generation (SHG) can be utilized to determine the exact nature of nanotwins in noncentrosymmetric crystals, which is challenging to resolve via conventional transmission electron or scanned probe microscopies. Using single-crystalline nanotwinned CdTe nanobelts and nanowires as a model system, we show that SHG polarimetry can distinguish between upright (Cd-Te bonds) and inverted (Cd-Cd or Te-Te bonds) twin boundaries in the system. Inverted twin boundaries are generally not reported in nanowires due to the lack of techniques and complexity associated with the study of the nature of such defects. Precise characterization of the nature of defects in nanocrystals is required for deeper understanding of their growth and physical properties to enable their application in future devices.
authors.affiliation: Department of Materials Science and Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Ming-Liang
authors.initials: ML
authors.lastname: Ren
authors.affiliation: Department of Materials Science and Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Rahul
authors.initials: R
authors.lastname: Agarwal
authors.affiliation: Department of Materials Science and Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Pavan
authors.initials: P
authors.lastname: Nukala
authors.affiliation: Department of Materials Science and Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Wenjing
authors.initials: W
authors.lastname: Liu
authors.affiliation: Department of Materials Science and Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Ritesh
authors.initials: R
authors.lastname: Agarwal
keywords: Second harmonic generation; crystal structure; nanowire; nonlinear optics; transmission electron microscope; twin boundary