Rolled‐up Nanotechnology: Materials Issue and Geometry Capability

Abstract

chemical vapor deposition (CVD). When it comes to on-chip integrations, these strategies are limited by accessible materials and slow processing rate, [31] and the generated defects in the produced amorphous materials placed restrictions to its further applications in high-performance devices. [32] Therefore, novel approaches and methods of fabricating 3D micro/ nanostructures are highly demanded.Rolled-up nanotechnology is an alternative technique that fabricates 3D nanostructures out of planar films called nanomembranes. Nanomembranes are defined as planar thin films with thicknesses between one to a few hundred nanometers. [33] These nanomembrane materials behave like soft materials while maintaining excellent properties like their bulk counterpart and therefore is an ideal platform for fabricating 3D nanostructures. Inspired by concepts of origami and kirigami, [34][35][36][37] researchers folded and rolled these nanomembranes into a number of fascinating 3D structures. [17,[38][39][40][41][42][43][44] Several review articles have been published with emphasis on nanomembranes thinning and manufacture, mechanical deformation, fundamental studies, and their practical applications. [33,41,[45][46][47] By releasing strain-engineered planar functional nanomembranes on sacrificial layers, complex rolled-up structures including tubes, [48][49][50][51][52][53][54] rings, [54][55][56] and helices [42,[57][58][59] can be constructed (for instance, see Figure 1f). This approach can be applied to engineer a wide range of organic and inorganic materials and their combinations, including metals, insulators, traditional semiconductor families, and recently emerged 2D materials. Given its compatibility to standard CMOS fabrication process and ability to manufacture large periodic arrays with precise geometric control, rolled-up nanotechnology further expands the applications of 3D nanostructures to a number of areas, including optical resonators, [60,61] photodetectors, [62,63] micromotors, [64][65][66] energy storage, [67] drug delivery, [68] gas detection, [53] and environmental decontamination. [69] The versatility in the materials design and geometric tuning in rolled-up nanotechnology presents tremendous opportunities for further developing sophisticated 3D fine structures.In this review, we focus on the materials perspective and fabrication process of rolled-up nanotechnology. First, we give a brief introduction of rolled-up mechanism, as well as its fabrication techniques and control strategies. We summarize and highlight recent advances of different materials systems and their corresponding rolling methodologies. Second, Rolled-up nanotechnology is an appealing technique that tunes planar films into complex 3D fine structures. The rolling-up mechanism and methodology of a huge variety of materials and their combinations are summarized, including metals, insulators, traditional semiconductor families, polymers, and recently emerged 2D materials. The basic principles of strain induction, fabrication methods, and techni...

Shapeable Material Technologies for 3D Self‐Assembly of Mesoscale Electronics

“…With the help of compatible lithographic techniques and, more importantly, development of novel lithographically processable strain‐engineering materials and composites, the self‐assembly of micro‐ and nanoscale 3D architectures can be obtained by the shaping of initially planar structures . These shapeable material technologies have already demonstrated (Figure b) the capability to self‐assemble planar films into a number of different complex polygonal structures and tubular “Swiss‐rolls.”…”

Transformable, Freestanding 3D Mesostructures Based on Transient Materials and Mechanical Interlocking

“…Complex 3D functional systems are of widespread interest due to their potential applications in areas ranging from biomedical devices and metamaterials to electronic platforms . Although fabrication techniques based on 3D printing, templated growth, and controlled folding/rolling are useful in many contexts, each has limitations in materials compatibility, accessible feature size or, most critically, alignment with state‐of‐the‐art 2D processing techniques used in the semiconductor industry. A portfolio of recently presented methods allow geometric transformation of such 2D systems (referred to here as 2D precursors) into 3D structures by the action of compressive forces delivered at precisely defined locations via a prestretched silicone elastomer substrate .…”

3D Self‐Assembled Microelectronic Devices: Concepts, Materials, Applications

“…The materials and techniques necessary for self‐assembly on the mesoscopic scale has progressed rapidly over the last two decades, and it has certainly experienced an increased level of interest in the past few years as is evident from the recent proliferation of reviews on the topic . The techniques associated with self‐assembled devices as well as their material platforms are reviewed in this section to bring the various parts of the self‐assembly toolbox to the readers' attention.…”