Pressure-Induced Orientation Control of the Growth of Epitaxial Silicon Nanowires

Abstract

Single crystal silicon nanowires (SiNWs) were synthesized with silane reactant using Au nanocluster-catalyzed one-dimensional growth. We have shown that under our experimental conditions, SiNWs grown epitaxially on Si(111) via the vapor-liquid-solid growth mechanism change their growth direction as a function of the total pressure. Structural characterization of a large number of samples shows that SiNWs synthesized at a total pressure of 3 mbar grow preferentially in the 111 direction, while the one at 15 mbar favors the 112 direction. Specifically by dynamically changing the system pressure during the growth process morphological changes of the NW growth directions along their length have been demonstrated.

Structural and tunneling properties of Si nanowires

“…Recently the synthesis of diameters below 10 nm has been achieved. 7 It has been demonstrated that Si NWs are rodlike structures with a bulk Si single crystalline core 8 and thus grow along well-defined crystalline directions 9,10 and follow the Si surface reconstruction criteria according to Wulff's minimum energy law, 11 thereby having a well defined shape in their cross section. 12 Due to the sp 3 nature of the Si bonding, the atoms at the surface have dangling bonds, 13 which need to be passivated in order to ensure chemical stability.…”

Role of Defects and Growth Directions in the Formation of Periodically Twinned and Kinked Unseeded Germanium Nanowires

“…24,27,28 Careful control over the growth 5 orientation is particularly important when epitaxial growth from crystalline substrates is desired. 29,30 Structural variations within NWs, such as lamellar twinning faults, have been noted in a number of seeded approaches and must be understood and controlled as they can impact the electrical and optical properties of the NWs. 31 Faults parallel and perpendicular to either the <111> or <112> growth direction of Si and Ge NWs have been shown in a number of studies [31][32][33] while more complex 10 morphological variations such as NW kinking often occurs as a result of a change in growth direction in single crystal NWs.…”

Ordered arrays of epitaxial silicon nanowires produced by nanosphere lithography and chemical vapor deposition

“…With this goal in mind, we choose a low SiH 4 concentration at low pressure (also reported in Ref. [29]) for the CVD process, which corresponds with slower growth kinetics. Fig.…”