Control of GaAs nanowire morphology by group III precursor chemistry

• Published in: Journal of crystal growth Vol. 325; no. 1; pp. 5 - 9
• Main Authors: Salehzadeh, O., Watkins, S.P.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.06.2011; Elsevier
• Subjects: A1. Nanostructures; A1. Surface processes; A2. Crystal morphology; A3. Metalorganic vapor phase epitaxy; B1. Gallium compounds; B2. Semiconducting III–V materials; Chemical synthesis methods; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Gallium arsenide; Gallium arsenides; Heterostructures; Indium arsenides; Materials science; Methods of crystal growth; physics of crystal growth; Methods of nanofabrication; Nanocomposites; Nanomaterials; Nanoscale materials and structures: fabrication and characterization; Nanostructure; Nanowires; Physics; Precursors; Quantum wires; Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation; A3. Metalorganic vapor phase epitaxy; A1. Surface processes; B1. Gallium compounds; B2. Semiconducting III–V materials; A2. Crystal morphology; A1. Nanostructures; Gallium arsenides; Gallium; Growth rate; VPE; Nanostructures; Precursor; B2. Semiconducting III-V materials; Crystal morphology; Gallium compounds; Nanomaterial synthesis; Temperature dependence; Core shell structure; VLS growth; Lateral growth; Indium arsenides; III-V compound; Operating conditions; Surface reactions; MOVPE method; Growth mechanism; Nanowires; Nanostructured materials; Heterostructures; III-V semiconductors
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2011.04.039

In this work we show that the choice of Ga precursors has a striking effect on the growth kinetics of GaAs nanowires grown by metalorganic vapor phase epitaxy (MOVPE) using the vapor–liquid–solid (VLS) growth mechanism. We investigate the detailed temperature dependence of nanowire axial and lateral growth rates using two different Ga sources, trimethylgallium (TMGa) and triethylgallium (TEGa), in conjunction with tertiarybutylarsine. We observed dramatically enhanced tapering for TEGa compared with TMGa, which is attributed to lateral growth resulting from a much lower decomposition temperature of TEGa. For both precursors, the competition between vapor–solid (VS) and VLS surface reaction rates is the primary determinant of nanowire morphology. The results show strong evidence of the catalytic effect of Au on the total mass growth rate for the case of TMGa growth. We demonstrate the usefulness of precursor chemistry in controlling InAs/GaAs heterostructure growth. Axial InAs/GaAs heterostructures were grown using trimethylindium (TMIn) and TMGa. In contrast, core–shell InAs/GaAs heterostructures are achieved using TMIn/TEGa under the same growth conditions. ► First detailed study of comparison of different precursors in the growth of GaAs nanowires. ► Clear evidence for the role of Au catalyst in nanowire growth. ► Demonstration of the ability to switch between axial and core–shell heterostructures growth by means of precursor chemistry.