Evolution of Epitaxial InAs Nanowires on GaAs (111)B

Abstract

The evolution of InAs nanowires on the GaAs (111)B substrate by metal–organic chemical vapor deposition shows that InAs traces are formed and elongated first, driven by the liquid Au catalysts preferentially retaining interfaces with the GaAs substrate due to the Au/GaAs interfacial energy being lower than that of Au/InAs. Vertical InAs nanowires initiate when elongated traces intersect (see image).

Crystallographically driven Au catalyst movement during growth of InAs/GaAs axial nanowire heterostructures

“…Our extensive TEM investigations showed that over 95% observed nanowires were associated Au sliding. As demonstrated in our earlier studies, 10,13 Au catalysts prefer to retain interfaces with GaAs and this drives the downward growth of InAs nanowires led by the Au catalysts. This growth behavior of InAs is indicated by an arrow in Fig.…”

Catalyst-free growth of InP nanowires on patterned Si (001) substrate by using GaAs buffer layer

“…3. In the part (a), since there exists a 4.2% difference in the lattice parameters between GaAs (aGaAs¼0.565 nm) and InP (aInP ¼0.587 nm), there will be many {111} type microtwins and stacking faults parallel to the InP/GaAs interface when InP nucleate on GaAs buffer layers (labeled by a dot line in InP nanowires) [14]. These twins/stacking faults can relieve misfit strain between InP and GaAs, which is caused by the formation of a/6 〈112〉 type partial dislocations.…”

“…However in this sample, a [1 À 12] direction InP nanowire was observed. There will be many {111} type microtwins and stacking faults parallel to the InP/GaAs interface when InP nucleate on GaAs buffer layers [14]. Those dislocations can effectively reduce the strain energy of InP crystal and make it easier growth aligned in 〈1 À12〉 directions.…”

Polarity driven simultaneous growth of free-standing and lateral GaAsP epitaxial nanowires on GaAs (001) substrate

“…1(c) is a SEM back-scattered electron image and reveals the presence of particles with heavier element(s) at the tip of lateral nanowires, which should be the Au catalysts we used to induce the nanowire growth. 24 Figure 1(d) is a schematic diagram to illustrate our observation of the simultaneously grown free-standing and lateral nanowires.…”

“…During annealing, surface As atoms may evaporate, leaving behind more free Ga atoms to form an alloy with the Au particles. 31 Since the interfacial energy of Au-Ga particle has a minimum with GaAs {111} planes, 24,32 the particle dissolves the original (001) surface, and forms a pit with four {111} planes of the GaAs substrate with ð 1 11Þ and (111) (belonging to {111} A planes -the red planes in Fig. 4); and ð 111Þ and ð1 11Þ (belonging to {111} B planesthe green planes in Fig.…”