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Catalyst composition and impurity-dependent kinetics of nanowire heteroepitaxy.


Type

Article

Change log

Authors

Gamalski, Andrew D 
Perea, Daniel E 
Yoo, Jinkyoung 
Li, Nan 
Olszta, Matthew J 

Abstract

The mechanisms and kinetics of axial Ge-Si nanowire heteroepitaxial growth based on the tailoring of the Au catalyst composition via Ga alloying are studied by environmental transmission electron microscopy combined with systematic ex situ CVD calibrations. The morphology of the Ge-Si heterojunction, in particular, the extent of a local, asymmetric increase in nanowire diameter, is found to depend on the Ga composition of the catalyst, on the TMGa precursor exposure temperature, and on the presence of dopants. To rationalize the findings, a general nucleation-based model for nanowire heteroepitaxy is established which is anticipated to be relevant to a wide range of material systems and device-enabling heterostructures.

Description

Keywords

nanowire, Ge-Si heteroepitaxy, nucleation barrier, environmental transmission electron microscopy, AuGa catalyst alloy, dopants

Journal Title

ACS Nano

Conference Name

Journal ISSN

1936-0851
1936-086X

Volume Title

7

Publisher

American Chemical Society (ACS)
Sponsorship
European Research Council (279342)
S.H. acknowledges funding from ERC grant InsituNANO (No. 279342). A.D.G. acknowledges funding from the Marshall Aid Commemoration Commission and the National Science Foundation. C.D. acknowledges funding from the Royal Society. A portion of the research was also performed using EMSL, a national scientific user facility sponsored by the Department of Energy’s (DOE) Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory (PNNL). PNNL is operated by Battelle for the U.S. DOE under Contract DE-AC05-76RL01830. We gratefully acknowledge the use of facilities within the LeRoy Eyring Center for Solid State Science at Arizona State University. This work was performed in part at CINT, a U.S. DOE, Office of Science User Facility. The research was funded in part by the Laboratory Directed Research and Development Program at LANL, an affirmative action equal opportunity employer operated by Los Alamos National Security, LLC, for the National Nuclear Security Administration of the U.S. DOE under Contract DE-AC52-06NA25396.