title: Scalable solution-phase epitaxial growth of symmetry-mismatched heterostructures on two-dimensional crystal soft template.
abstract: Epitaxial heterostructures with precisely controlled composition and electronic modulation are of central importance for electronics, optoelectronics, thermoelectrics, and catalysis. In general, epitaxial material growth requires identical or nearly identical crystal structures with small misfit in lattice symmetry and parameters and is typically achieved by vapor-phase depositions in vacuum. We report a scalable solution-phase growth of symmetry-mismatched PbSe/Bi2Se3epitaxial heterostructures by using two-dimensional (2D) Bi2Se3nanoplates as soft templates. The dangling bond-free surface of 2D Bi2Se3nanoplates guides the growth of PbSe crystal without requiring a one-to-one match in the atomic structure, which exerts minimal restriction on the epitaxial layer. With a layered structure and weak van der Waals interlayer interaction, the interface layer in the 2D Bi2Se3nanoplates can deform to accommodate incoming layer, thus functioning as a soft template for symmetry-mismatched epitaxial growth of cubic PbSe crystal on rhombohedral Bi2Se3nanoplates. We show that a solution chemistry approach can be readily used for the synthesis of gram-scale PbSe/Bi2Se3epitaxial heterostructures, in which the square PbSe (001) layer forms on the trigonal/hexagonal (0001) plane of Bi2Se3nanoplates. We further show that the resulted PbSe/Bi2Se3heterostructures can be readily processed into bulk pellet with considerably suppressed thermal conductivity (0.30 W/m·K at room temperature) while retaining respectable electrical conductivity, together delivering a thermoelectric figure of meritZTthree times higher than that of the pristine Bi2Se3nanoplates at 575 K. Our study demonstrates a unique epitaxy mode enabled by the 2D nanocrystal soft template via an affordable and scalable solution chemistry approach. It opens up new opportunities for the creation of diverse epitaxial heterostructures with highly disparate structures and functions.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA.
authors.forename: Zhaoyang
authors.initials: Z
authors.lastname: Lin
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA.
authors.forename: Anxiang
authors.initials: A
authors.lastname: Yin
authors.affiliation: Department of Physics and Texas Center for Superconductivity at the University of Houston, University of Houston, Houston, TX 77204, USA.
authors.forename: Jun
authors.initials: J
authors.lastname: Mao
authors.affiliation: Department of Materials Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Xia
authors.affiliation: Department of Mechanical and Biomedical Engineering, Boise State University, Boise, ID 83725, USA.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Kempf
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA.
authors.forename: Qiyuan
authors.initials: Q
authors.lastname: He
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA.
authors.forename: Yiliu
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA.
authors.forename: Chih-Yen
authors.initials: CY
authors.lastname: Chen
authors.affiliation: Department of Mechanical and Biomedical Engineering, Boise State University, Boise, ID 83725, USA.
authors.forename: Yanliang
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Materials Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA.
authors.forename: Vidvuds
authors.initials: V
authors.lastname: Ozolins
authors.affiliation: Department of Physics and Texas Center for Superconductivity at the University of Houston, University of Houston, Houston, TX 77204, USA.
authors.forename: Zhifeng
authors.initials: Z
authors.lastname: Ren
authors.affiliation: Department of Materials Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA.; California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA.
authors.forename: Yu
authors.identifier: 0000-0003-1793-0741
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA.; California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA.
authors.forename: Xiangfeng
authors.initials: X
authors.lastname: Duan
keywords: 2D crystals; atomic layer; epitaxial growth; heterostructure; superlattice; template; thermal conductivity; thermoelectric property