Growth of Pure Zinc-Blende GaAs(P) Core-Shell Nanowires with Highly Regular Morphology.

Yunyan Zhang,Huiyun Liu,James A Gott,Martin Aagesen,Pamela Jurczak,Suguo Huo,Dongyoung Kim,Jiang Wu,H Aruni Fonseka,Ana M Sanchez

doi:10.1021/acs.nanolett.7b02063

Abstract

The growth of self-catalyzed core-shell nanowires (NWs) is investigated systematically using GaAs(P) NWs. The defects in the core NW are found to be detrimental for the shell growth. These defects are effectively eliminated by introducing beryllium (Be) doping during the NW core growth and hence forming Be-Ga alloy droplets that can effectively suppress the WZ nucleation and facilitate the droplet consumption. Shells with pure zinc-blende crystal quality and highly regular morphology are successfully grown on the defect-free NW cores and demonstrated an enhancement of one order of magnitude for room-temperature emission compared to that of the defective shells. These results provide useful information on guiding the growth of high-quality shell, which can greatly enhance the NW device performance.

Highlights

S emiconductor nanowires (NWs) have considerable advantages over conventional planar semiconductors, such as efficient strain relaxation, reduced materials consumption, high aspect ratio, waveguiding ability, and enhanced light-trapping properties.[1−6] These unique properties offer NWs enormous versatility as novel nanoscale building blocks for the generation of semiconductor devices.1718 they have demonstrated the applications in areas, such as photovoltaics, light emitters, electron transistors, chemical, biological sensors, and so on.[7−14] Shell growth is a fundamental way to construct lateral homo- and heterojunctions
Shells with pure zinc-blende crystal quality and highly regular morphology are successfully grown on the defect-free NW cores and demonstrated an enhancement of one order of magnitude for room-temperature emission compared to that of the defective shells
Due to the unconsumable nature, those catalysts cannot be removed in situ, and their existence can lead to continued axial growth that competes with the lateral shell growth, which leads to sharppencil-like shell morphology.[24]

Summary

Introduction

S emiconductor nanowires (NWs) have considerable advantages over conventional planar semiconductors, such as efficient strain relaxation, reduced materials consumption, high aspect ratio, waveguiding ability, and enhanced light-trapping properties.[1−6] These unique properties offer NWs enormous versatility as novel nanoscale building blocks for the generation of semiconductor devices.1718 they have demonstrated the applications in areas, such as photovoltaics, light emitters, electron transistors, chemical, biological sensors, and so on.[7−14] Shell growth is a fundamental way to construct lateral homo- and heterojunctions. The NW tips with improper droplet consumption are commonly observed to have a high density of stacking faults.[32] These defects extend to the shell and degrade its crystal quality, as the shell is copying the lattice template from the core. The defects in the core NWs were found to degrade the shell morphology and crystal quality.

Results

Conclusion