Abstract
Based on a thermodynamic model, we quantify the impact of adding silicon atoms to a catalyst droplet on the nucleation and growth of ternary III–V nanowires grown via the self-catalyzed vapor–liquid–solid process. Three technologically relevant ternaries are studied: InGaAs, AlGaAs and InGaN. For As-based alloys, it is shown that adding silicon atoms to the droplet increases the nanowire nucleation probability, which can increase by several orders magnitude depending on the initial chemical composition of the catalyst. Conversely, silicon atoms are found to suppress the nucleation rate of InGaN nanowires of different compositions. These results can be useful for understanding and controlling the vapor–liquid–solid growth of ternary III–V nanowires on silicon substrates as well as their intentional doping with Si.
Highlights
Epitaxial growth of ternary III–V compounds [1] enables delicate bandgap engineering which is paramount for optoelectronic applications [2,3,4,5,6]
Due to their high surface-to-volume ratio and small footprint with the substrate, nanowire (NW) structures allow for a very efficient strain relaxation at the free lateral facets [10,11,12,13]. This property opens a way for nearly unlimited compositional tuning in ternary III–V NWs, including some material combinations that can hardly be achieved in thin films, as well as dislocation-free growth of such NWs on silicon substrates [14,15,16,17]
We apply the model to the three important ternary III–V NWs
Summary
Epitaxial growth of ternary III–V compounds [1] enables delicate bandgap engineering which is paramount for optoelectronic applications [2,3,4,5,6]. We consider a ternary III–V NW growing via the VLS process from a liquid catalyst droplet which contains, in addition to the three growth species, a small fraction of Si atoms. Pairs in pure solid binaries, respectively, which depend only on temperature T [31,32], According to Reference [28], the composition of a ternary sNW can be determined by m is the number of growth elements present in the droplet, ωAD−BD is the temperatureminimizing the corresponding formation energy F with respect to x dependent interaction parameter between AD and BD pairs in solid, and ωαβ are the. III–V NWs by calculating the function ρ given by Equations (5)–(7) This function contains the solid composition x, which is why the self-consistent determination of ρ requires a relationship between the compositions of ternary NW and the liquid droplet. Equation (11) should generally be solved numerically in order to precisely determine the compositional diagram y(x) at high group V concentrations
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