Freestanding SiGe/Si/Cr and SiGe/Si/SixNy/Cr microtubes

Abstract

We report on hybrid microtubes and rings fabricated from rolled-up strained metal–semiconductor SiGe/Si/Cr and metal–insulator–semiconductor SiGe/Si/SixNy/Cr films. For making suspended microtubes, a method of directional rolling of the patterned films by anisotropic underetching of silicon substrate was introduced. It is shown quantitatively that Cr and SixNy layers are highly strained, the tensile stress being sufficient to cause the rolling-up of the hybrid films into microtubes of preset diameter. The proposed controllable and reproducible technology is promising for fabricating cylindrical-shaped microcapacitors, induction coils, transistors, and building blocks of microelectromechanical devices.

Precise, molecularly thin semiconductor shells: from nanotubes to nanocorrugated quantum systems

“…The cornerstone stages in the development of this fabrication technology enabling precise formation of variously shaped shells from semiconductor and metal nano-objects include: (1) using highly selective etchants for the removal of sacrificial layers [1,2,16,18], (2) directional film rolling yielding threedimensional micro-and nanoshells of various shapes [8,9,12], (3) assembly of micro-and nanoshells in more complex architectures [3,4], (4) supercritical drying of nanoshells [11,14], (5) formation of nanoshells precisely controlled in all three dimensions [10], (6) elimination of surface oxidation in ultrathin layers, and (7) overgrowing or filling of shells [2].…”

“…By now, many pilot materials and devices using microtubes and spirals have become known [3,4,6,12,13,16,17]. These are new instruments for biology and medicine [12], micro-and nanoneedles, probes, and syringes, dispensable singlecrystal micro-and nanoneedles, electrodes, AFM probes, syringes, nanojet arrays, nanofibre-based composites [15], elastic chemically active fast sensors, supersensitive quantum sensors, optical actuators, optical microtube ring resonators [44], etc.…”

Scrolled Si/SiGe Heterostructures as Building Blocks for Tube‐Like Field‐Effect Transistors

“…We note that the radius value calculated using this model is in a good agreement with the available experimental data. 30 The strain distribution strongly affects position of the conduction and valence band. Hydrostatic strain shifts the energy position of bands, while biaxial strain splits the degenerate bands.…”

Molecularly and atomically thin semiconductor and carbon nanoshells

“…A promising field where 3D shells can find application is the development of metamaterials with negative refraction and optically active materials. The approach developed in our works can be used to create chiral spiral structures [20,21], optically active materials [20], and metamaterials based on optically active materials. Arrays of precise hybrid metal-semiconductor microhelices were recently fabricated from strained bifilms [20].…”