Templated dewetting of single-crystal sub-millimeter-long nanowires and on-chip silicon circuits

Abstract

Large-scale, defect-free, micro- and nano-circuits with controlled inter-connections represent the nexus between electronic and photonic components. However, their fabrication over large scales often requires demanding procedures that are hardly scalable. Here we synthesize arrays of parallel ultra-long (up to 0.75 mm), monocrystalline, silicon-based nano-wires and complex, connected circuits exploiting low-resolution etching and annealing of thin silicon films on insulator. Phase field simulations reveal that crystal faceting and stabilization of the wires against breaking is due to surface energy anisotropy. Wires splitting, inter-connections and direction are independently managed by engineering the dewetting fronts and exploiting the spontaneous formation of kinks. Finally, we fabricate field-effect transistors with state-of-the-art trans-conductance and electron mobility. Beyond the first experimental evidence of controlled dewetting of patches featuring a record aspect ratio of 1/60000 and self-assembled mm long nano-wires, our method constitutes a distinct and promising approach for the deterministic implementation of atomically-smooth, mono-crystalline electronic and photonic circuits.

Programmable Single‐Crystalline PbI2 Microplate Arrays and Their Organic/Inorganic Heterojunctions

“…To fabricate horizontal arrays, ink-jet printing provides another common methodology to control the position of nucleation, which manipulates the crystallization through the regulation of inorganic precursors and dispersants in sols. [19,25,26] Owing to the coffee-ring and Marangoni effects, disordered capillary flows could prompt an uncontrollable mass transfer, yielding polycrystalline nanostructures with grain boundaries and surface defects, which restrict the device performance due to their large surface recombination rate and short carrier lifetime. [17,[27][28][29][30] Therefore, it is essential to fabricate programmable inorganic material patterns with full control over the position, morphology, size, crystallinity and defect density, which contribute to the implementation of electronic and photonic devices.…”

“…[ 15–18 ] To address this point, some approaches have been developed to control the position of inorganic nucleation, such as mold‐mediated methods and printing techniques. [ 19–21 ] For example, the anodized aluminum oxide (AAO) mold employs micro/nanosize channels to confine the crystallization of target inorganic materials, yielding vertically aligned nanostructure arrays with controllable size, shape, dimensions, and spacing. [ 22–24 ] However, compared with vertical arrays, horizontal arrays are more beneficial to the extensive applications in the integrated optoelectronic area.…”

Solid-State Dewetting Dynamics of Amorphous Ge Thin Films on Silicon Dioxide Substrates

“…Only nanowires with a diameter greater than 55 nm show a crystallization temperature of 500 °C, in agreement with that of bulk germanium [ 26 ]. The proposed interpretation is that oxygen atoms hinder both the formation and growth of crystallites by penetrating the nanowire more than the typical thickness of the native oxide, of the order of a few nm [ 28 , 29 ], thus interfering deeply with the crystallization dynamics in thin nanowires. The thickness of native oxide is typically not very stable under thermal treatments, being easily removed during annealing.…”

Doubly degenerate diffuse interface models of anisotropic surface diffusion

“…See, for example, the discussion in Backofen et al 25 . In fact, several simulations for realistic applications in materials science consider this model—see, for example, other studies 26‐38 —and claim that their large‐scale simulations would not be feasible without the additional degeneracy. The drawback of this DDCH model, which is termed RRV model in several publications, 22,31,36 is that it is nonvariational.…”