title: Facile Five-Step Heteroepitaxial Growth of GaAs Nanowires on Silicon Substrates and the Twin Formation Mechanism.
abstract: Monolithic integration of III-V semiconductors with Si has been pursued for some time in the semiconductor industry. However, the mismatch of lattice constants and thermal expansion coefficients represents a large technological challenge for the heteroepitaxial growth. Nanowires, due to their small lateral dimension, can relieve strain and mitigate dislocation formation to allow single-crystal III-V materials to be grown on Si. Here, we report a facile five-step heteroepitaxial growth of GaAs nanowires on Si using selective area growth (SAG) in metalorganic chemical vapor deposition, and we further report an in-depth study on the twin formation mechanism. Rotational twin defects were observed in the nanowire structures and showed strong dependence on the growth condition and nanowire size. We adopt a model of faceted growth to demonstrate the formation of twins during growth, which is well supported by both a transmission electron microscopy study and simulation based on nucleation energetics. Our study has led to twin-free segments in the length up to 80 nm, a significant improvement compared to previous work using SAG. The achievements may open up opportunities for future functional III-V-on-Si heterostructure devices.
authors.affiliation: Ming Hsieh Department of Electrical Engineering, ‡Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, §Mork Family Department of Chemical Engineering and Materials Science, and ∥Center for Energy Nanoscience, University of Southern California , Los Angeles, California 90089, United States.
authors.forename: Maoqing
authors.initials: M
authors.lastname: Yao
authors.affiliation: Ming Hsieh Department of Electrical Engineering, ‡Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, §Mork Family Department of Chemical Engineering and Materials Science, and ∥Center for Energy Nanoscience, University of Southern California , Los Angeles, California 90089, United States.
authors.forename: Chunyang
authors.initials: C
authors.lastname: Sheng
authors.affiliation: Ming Hsieh Department of Electrical Engineering, ‡Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, §Mork Family Department of Chemical Engineering and Materials Science, and ∥Center for Energy Nanoscience, University of Southern California , Los Angeles, California 90089, United States.
authors.forename: Mingyuan
authors.initials: M
authors.lastname: Ge
authors.affiliation: Ming Hsieh Department of Electrical Engineering, ‡Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, §Mork Family Department of Chemical Engineering and Materials Science, and ∥Center for Energy Nanoscience, University of Southern California , Los Angeles, California 90089, United States.
authors.forename: Chun-Yung
authors.initials: CY
authors.lastname: Chi
authors.affiliation: Ming Hsieh Department of Electrical Engineering, ‡Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, §Mork Family Department of Chemical Engineering and Materials Science, and ∥Center for Energy Nanoscience, University of Southern California , Los Angeles, California 90089, United States.
authors.forename: Sen
authors.initials: S
authors.lastname: Cong
authors.affiliation: Ming Hsieh Department of Electrical Engineering, ‡Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, §Mork Family Department of Chemical Engineering and Materials Science, and ∥Center for Energy Nanoscience, University of Southern California , Los Angeles, California 90089, United States.
authors.forename: Aiichiro
authors.initials: A
authors.lastname: Nakano
authors.affiliation: Ming Hsieh Department of Electrical Engineering, ‡Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, §Mork Family Department of Chemical Engineering and Materials Science, and ∥Center for Energy Nanoscience, University of Southern California , Los Angeles, California 90089, United States.
authors.forename: P Daniel
authors.initials: PD
authors.lastname: Dapkus
authors.affiliation: Ming Hsieh Department of Electrical Engineering, ‡Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, §Mork Family Department of Chemical Engineering and Materials Science, and ∥Center for Energy Nanoscience, University of Southern California , Los Angeles, California 90089, United States.
authors.forename: Chongwu
authors.initials: C
authors.lastname: Zhou
keywords: GaAs on Si; MOCVD; TEM; heteroepitaxy; nanowires; thermodynamics; twin defect