A General Approach for Sharp Crystal Phase Switching in InAs, GaAs, InP, and GaP Nanowires Using Only Group V Flow

Abstract

III-V-based nanowires usually exhibit random mixtures of wurtzite (WZ) and zinc blende (ZB) crystal structure, and pure crystal phase wires represent the exception rather than the rule. In this work, the effective group V hydride flow was the only growth parameter which was changed during MOVPE growth to promote transitions from WZ to ZB and from ZB to WZ. Our technique works in the same way for all investigated III-Vs (GaP, GaAs, InP, and InAs), with low group V flow for WZ and high group V flow for ZB conditions. This strongly suggests a common underlying mechanism. It displays to our best knowledge the simplest changes of the growth condition to control the nanowire crystal structure. The inherent reduction of growth variables is a crucial requirement for the interpretation in the frame of existing understanding of polytypism in III-V nanowires. We show that the change in surface energetics of the vapor-liquid-solid system at the vapor-liquid and liquid-solid interface is likely to control the crystal structure in our nanowires.

InP–InxGa1−xAs core-multi-shell nanowire quantum wells with tunable emission in the 1.3–1.55 μm wavelength range

“…This considerable difference is due to two reasons. First, the equivalent facet orientation of nanowires in the ZB phase itself is different from (100), and they generally grow slower than (100) facets under the considered growth conditions (for example {110} and {112} face growth rate of the side facets of nanowires in WZ phase is inherently even lower than th equivalent, 44,52 making the actual thickness much lower than expected. However, the growth rate of the QWs seems to remain constant thickness with growth time.…”

Electron-hole interactions in coupled InAs-GaSb quantum dots based on nanowire crystal phase templates

“…18 The molar fraction of AsH 3 was set to 2.3×10 −5 , and 2.5×10 −2 , for WZ and ZB respectively, while TMIn was kept at 1.8×10 −6 , for both crystal phases. The TMGa and TMSb flows for the GaSb shell were both set to 2.7×10 −5 .…”

XXI Международный симпозиум Нанофизика и наноэлектроника", Нижний Новгород, 13-16 марта 2017 г. Нитевидные нанокристаллы GaP/Si (111), синтезированные методом молекулярно-пучковой эпитаксии с переключением гексагональной и кубической фазy -=SUP=-*-=/SUP=-

“…Верхняя граница для химических потенциалов является доста-точно резкой, т. е. вблизи µ max ННК растут либо в одной, либо в другой фазе [8][9][10][11][12][13]. Рост ННК вблизи нижней границы может происходить с образованием политипов [10,[13][14][15][16].…”