nl7b03366_si_001.pdf (211.29 kB)
Doping of Self-Catalyzed Nanowires under the Influence of Droplets
journal contribution
posted on 2017-12-05, 17:18 authored by Yunyan Zhang, Zhiyuan Sun, Ana M. Sanchez, Manfred Ramsteiner, Martin Aagesen, Jiang Wu, Dongyoung Kim, Pamela Jurczak, Suguo Huo, Lincoln J. Lauhon, Huiyun LiuControlled and reproducible
doping is essential for nanowires (NWs)
to realize their functions. However, for the widely used self-catalyzed
vapor–liquid–solid (VLS) growth mode, the doping mechanism
is far from clear, as the participation of the nanoscale liquid phase
makes the doping environment highly complex and significantly different
from that of the thin film growth. Here, the doping mechanism of self-catalyzed
NWs and the influence of self-catalytic droplets on the doping process
are systematically studied using beryllium (Be) doped GaAs NWs. Be
atoms are found for the first time to be incorporated into NWs predominantly
through the Ga droplet that is observed to be beneficial for setting
up thermodynamic equilibrium at the growth front. Be dopants are thus
substitutional on Ga sites and redundant Be atoms are accumulated
inside the Ga droplets when NWs are saturated, leading to the change
of the Ga droplet properties and causing the growth of phase-pure
zincblende NWs. This study is an essential step toward the design
and fabrication of nanowire devices.