Fiber draw synthesis

Abstract

The synthesis of a high-melting temperature semiconductor in a low-temperature fiber drawing process is demonstrated, substantially expanding the set of materials that can be incorporated into fibers. Reagents in the solid state are arranged in proximate domains within a fiber preform. The preform is fluidized at elevated temperatures and drawn into fiber, reducing the lateral dimensions and bringing the domains into intimate contact to enable chemical reaction. A polymer preform containing a thin layer of selenium contacted by tin-zinc wires is drawn to yield electrically contacted crystalline ZnSe domains of sub-100-nm scales. The in situ synthesized compound semiconductor becomes the basis for an electronic heterostructure diode of arbitrary length in the fiber. The ability to synthesize materials within fibers while precisely controlling their geometry and electrical connectivity at submicron scales presents new opportunities for increasing the complexity and functionality of fiber structures.flexible electronics | optical fiber processing | semiconductor device T hermal fiber drawing is a process in which a macrostructured preform is heated and drawn into extended lengths of microstructured fiber. New methods of increasing both the structural complexity of fibers and number of materials compatible with the drawing process are substantially expanding the functionality of photonic crystal and semiconductor device fibers (1-3). The drawing process, however, has until now been limited to materials that flow at the draw temperature. Approaches that attempt to circumvent this limitation include depositing materials inside (4-7) or onto the surface (8-11) of previously drawn fiber substrates. These methods do not take full advantage of the scaling associated with fiber drawing and are limited in their geometric complexity and the length over which uniform structures can be produced. Here this seemingly fundamental limitation is lifted by utilizing the fiber drawing process to synthesize in situ a chemical compound that has a melting temperature far exceeding the draw temperature. In this process, precursors are arranged in adjacent domains in a macroscopic preform. During thermal drawing, the fluid reactants come into contact and precipitate a new compound. To demonstrate the potential of this fiber draw synthesis method, a polymer fiber preform containing a thin seleniumsulfur layer next to eutectic tin-zinc wires is constructed and thermally codrawn into a fiber consisting of electrically contacted crystalline ZnSe domains of sub-100-nm scales at the interface between the metallic domains and selenium layer. The formation of the interface compound is the basis for an electronic heterostructure and a thermally drawn fiber device exhibiting rectifying behavior. The ability to synthesize materials during the fiber draw process while maintaining precise and arbitrary geometries should lead to substantial advances in the form and function of fibers. Results and DiscussionA fiber preform consisting of metallic Sn 74 P...

Hybrid Optical Fibers – An Innovative Platform for In‐Fiber Photonic Devices

“…[ 134 ] The only functional optoelectronic device using fi ber draw synthesis was recently presented where a Se 97 S 3 layer was brought in contact with a Sn 85 Zn 15 eutectic electrode. [ 106 ] It is argued in this study, and was investigated further later in a subsequent study by the same group, [ 133 ] that ZnSe compound was formed after diffusion of the Zn from the electrode and reaction with Se. This layer with a large bandgap in between the Se layer and the metal ( Figure 15 a), would explain the formation of a heterojunction that induced a barrier to the transport of holes.…”

“…Integrating semiconducting functionalities, traditionally reserved for smaller scale and rigid wafer substrates, inside fl exible 1D systems with the length and surface associated with optical fi bers, can herald a novel path towards large area, fl exible, and even wearable optoelectronic devices. Several applications can be envisioned and have been proposed for these one dimensional fi ber systems (as opposed to point devices) in imaging, [ 41,103,104 ] industrial monitoring, [ 105 ] remote and distributed sensing, [ 34,35 ] energy harvesting [ 75,106 ] and functional fabrics. [ 25,41,107 ] A promising strategy to realize this vision is to employ the multimaterial thermal drawing approach to directly integrate semiconducting materials in contact with metals and insulators in prescribed architectures.…”

“…[ 106,128,133 ] During thermal drawing, materials Figure 14. a) SEM micrograph of a solid chalcogenide glass core (As 52 Se 40 Te 8 ) fi ber after a post-drawing thermal annealing treatment that exhibits crystal growth nucleating for the most part from the interfacing crystalline electrodes.…”

Crystalline GaSb-core optical fibers with room-temperature photoluminescence

“…The literature on Group IV semiconductor-core glass fibers is now significant [1][2][3][4][5], including processing improvements [6][7][8] and device demonstrations [9][10][11][12][13][14][15][16][17]. There are also reports on both SiGe alloy and II-VI core fibers [18][19][20][21][22][23], one including low temperature photoluminescence [21]. However, there is limited information on III-V semiconductor-core fibers [26][27][28] manufactured by either CVD or molten-core techniques.…”

Crystalline silicon core fibres from aluminium core preforms

“…The placement of disparate materials thermally drawn into close proximity at elevated temperatures presents compelling opportunities for inducing chemical reactions between the constituent materials [26][27][28] that could in principle provide the versatility of chemical reactions with the scalability of fibre drawing. Results of this approach that we call fibre-draw synthesis to date have been confined to reactions in only very small domains at an interface between materials.…”