nl7b00123_si_002.pdf (1.23 MB)
Nonradiative Step Facets in Semiconductor Nanowires
journal contribution
posted on 2017-03-24, 00:00 authored by Ana M. Sanchez, Yunyan Zhang, Edward W. Tait, Nicholas D. M. Hine, Huiyun Liu, Richard BeanlandOne
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.