Effect of As preadsorption on InAs nanowire heteroepitaxy on Si(111): A first-principles study

Abstract

Arsenic preadsorption has recently been found to be crucial for selective-area epitaxial growth of oriented III-V semiconductor nanowires on Si͑111͒. To understand the effect of preadsorption on the heteroepitaxy, this first-principles study examines the structure of As-adsorbed Si͑111͒ surfaces. Reconstruction models such as adatom, trimer, and dimer-adatom-stacking fault structures are found to be metastable. The stability of unreconstructed arsenide structure ͑1 ϫ 1-As͒ is confirmed but the faulted and unfaulted domains of 1 ϫ 1-As are found to be practically degenerate in energy. These domains can therefore coexist on a Si͑111͒-As surface, and then epitaxial growth will be disrupted at domain boundaries where translational symmetry is broken. Indium adsorption on the Si͑111͒-As surface, however, destabilizes unfaulted domains, thus assisting its transformation into a coherent surface that allows epitaxy. This effect is attributed to the interlayer covalent interactions induced by In p electrons.

Heterogeneous nucleation of catalyst-free InAs nanowires on silicon

“…An Aspassivated silicon surface was found to have a very low surface energy due to the existence of As lone-pair states inducing Volmer-Weber (VW) growth of InAs islands [32]. Moreover, the As-passivated silicon surface was shown to resemble an InAs(111)B oriented surface, and nucleation of VW islands on such a surface resulted in a high yield of vertically oriented catalyst-free NWs [27,29,33]. Although the As-passivated silicon surface should be very stable [32], the passivation of the surface may still be incomplete due to the temperature dependence of adsorption and desorption of As atoms on silicon [31].…”

Influence of the oxide layer for growth of self-assisted InAs nanowires on Si(111)

“…This observation is much different than for growths using MOCVD, where advanced cool down procedures has been developed for obtaining vertical NWs [ 15 ]. A theoretical study by Koga describes how pre-adsorption of first As and then In assists the formation of a coherent surface and makes it possible to grow vertical NWs [ 18 ]. The difference between the two growth systems might be due to the necessary pre-cracking in an MOCVD growth system, or because of residuals from the cracking that affect the substrate surface.…”

High yield of self-catalyzed GaAs nanowire arrays grown on silicon via gallium droplet positioning

“…Although great progress has already been made in terms of material quality for III-V layers grown on silicon, structural defects are still a challenge for critical device applications, such as lasers and high mobility transistors. These defects include misfit and threading dislocations, due to the large lattice mismatch between most III-V and silicon [1,2], antiphase domain boundaries and cracks, due to polarity issues and thermal mismatch, respectively [3][4][5].…”