Nonradiative Step Facets in Semiconductor Nanowires.
One of the main advantages of nanowires for functional applications is their high perfection, which results from surface image forces that act on line defects such as dislocations, rendering them unstable and driving them out of the crystal. Here we show that there is a class of step facets that are stable in nanowires, with no long-range strain field or dislocation character. In zinc-blende semiconductors, they take the form of Σ3 (112) facets with heights constrained to be a multiple of three {111} monolayers. Density functional theory calculations show that they act as nonradiative recombination centers and have deleterious effects on nanowire properties. We present experimental observations of these defects on twin boundaries and twins that terminate inside GaAsP nanowires and find that they are indeed always multiples of three monolayers in height. Strategies to use the three-monolayer rule during growth to prevent their formation are discussed.
Department of Physics, University of Warwick , Coventry CV4 7AL, United Kingdom.
Ana M
0000-0002-8230-6059
AM
Sanchez
Department of Electronic and Electrical Engineering, University College London , Torrington Place, London WC1E 7JE, United Kingdom.
Yunyan
Y
Zhang
TCM Group, Cavendish Laboratory , 19 JJ Thomson Avenue, Cambridge, CB3 0HE, United Kingdom.
Edward W
EW
Tait
Department of Physics, University of Warwick , Coventry CV4 7AL, United Kingdom.
Nicholas D M
ND
Hine
Department of Electronic and Electrical Engineering, University College London , Torrington Place, London WC1E 7JE, United Kingdom.
Huiyun
H
Liu
Department of Physics, University of Warwick , Coventry CV4 7AL, United Kingdom.
Richard
R
Beanland
DFT; Nanowire; STEM; defects; step facets