Influence of growth parameters on In-droplet-assisted growth of InAs nanowires on silicon

Abstract

The influence of growth parameters on the morphology and density of InAs nanowires (NWs) grown on bare Si substrates using Indium (In) droplets as catalyst is investigated. By tuning the growth temperature, V/III flux ratio, and growth rate, the diameter and yield of asgrown NWs were controllably manipulated. It is demonstrated that the In-droplet-assisted growth of InAs NWs can only be realized on bare Si within a relatively narrow growth window of 420-475°C. Below 420°C, NWs' growth is kinetically limited, while the highest yield of vertically aligned NWs was obtained at *450°C. It is shown that In-catalyzed InAs NWs nucleation can only be realized on Si at highly As-rich conditions (V/III flux ratio [50), while the axial growth rate was found to be strongly dependent on the V/III flux ratio. The nucleation and axial growth of In-catalyzed InAs NWs are promoted by a low growth rate, while a high growth rate favors the formation of unwanted parasitic islands.

Low‐Temperature Growth of Au‐Catalyzed InAs Nanowires: Experiment and Theory

“…The axial growth rate of 4.4 nm s À1 obtained here is even higher than the maximum growth rate of Au-catalyzed InAs NWs grown by metal-organic vapor phase epitaxy at 450 C (3.1 nm s À1 ), [15] while the MBE growth rate at 450 C is below 1 nm s À1 . [16] This result is even more surprising if we consider that most In atoms remain in the parasitic islands between the NWs, clearly seen in Figure 1b. We attribute the large L h i=H ratio of our NWs to: 1) low temperature, which suppresses desorption of In from the substrate surface, NW sidewalls, or catalyst nanoparticles, and 2) narrow NW diameter.…”

“…The axial growth rate of 4.4 nm s −1 obtained here is even higher than the maximum growth rate of Au‐catalyzed InAs NWs grown by metal–organic vapor phase epitaxy at 450 °C (3.1 nm s −1 ), [ 15 ] while the MBE growth rate at 450 °C is below 1 nm s −1 . [ 16 ]…”

Self-Catalyzed InSb/InAs Quantum Dot Nanowires

“…As the growth temperature is increased, the NP become smaller and so both axial and radial growth rate decrease. Moreover, at high growth temperature In desorption starts to be sizable [ 60 ] so that both growth rates decrease. Moreover, considering the As-line pressure series, we found that when the growth conditions preserve an In droplet with β > 90° on top of the NWs, both axial and radial growths are enhanced by increasing F As , meaning that both VLS and VS growth are As-limited.…”

Growth of long III-As NWs by hydride vapor phase epitaxy

“…In self-catalyzed MBE, the indium catalyst is obtained either by in-situ deposition prior to growth [144] or by initiating growth under indium rich conditions [145]. The NW morphology is very sensitive to the growth parameters such as the temperature and the vapor phase composition.…”

“…In MBE and CBE, several groups showed that VS growth of InAs NWs was mainly limited by the surface diffusion of adatoms, which does not favor a pure crystalline quality of NWs that exhibit a high density of twin planes, stacking faults and alternating ZB/WZ segments along the growth axis [143,144,151]. MOVPE provided also very promising results in the case of SAG, even though the wires did not exhibit a pure crystalline quality all along the NWs length limited to few microns [152,153].…”