Selective‐Area Growth of Aligned Organic Semiconductor Nanowires and Their Device Integration

Abstract

The simultaneous control of the orientation and position of organic semiconductor nanowires remains a major challenge when integrating them into monolithic devices. In this study, tris(8‐hydroxyquinoline)aluminum(III) (Alq3) molecules are self‐assembled into single‐crystalline nanowires with consistent orientation and predictable positions by selective‐area graphoepitaxial growth. The nanowire orientation is determined by parallel nanogrooves on a periodically modified faceted sapphire surface, and the position is simultaneously defined using a shadow mask. Computational fluid dynamics simulations showed that the mass flow field over the sapphire surface is tailored by the mask, resulting in preferential nanowire nucleation around the hole centers and leaving sufficient free space for the subsequent growth. Accordingly, the number, length, and density of the nanowires can be controlled by adjusting the mask layout. The good alignment and predictable positions of these nanowires facilitated their subsequent device integration, eliminating laborious assembly steps and potential damage after nanowire growth. Measurements from an in situ integrated two‐terminal device based on the Alq3 nanowires revealed that the nanowires exhibit a remarkable negative differential resistance and fast photoresponse in the UV region. Overall, selective‐area graphoepitaxial growth provides a versatile protocol for fabricating site‐ and orientation‐controlled organic semiconductor nanowires for the monolithic fabrication of nanowire‐based devices.

Recent Advances in Functional Materials for Optical Data Storage

“…The construction of the nanoassembly will be useful for the design of novel organic–inorganic hybrid nanosystems for the bioimaging and enhancement of a FRET quenching effect in the UCNPs with DTDs. Intriguingly, the amphiphilic polymer shells containing photoresponsive DTE chromophores and UCNPs were prepared by the same group [ 70 ]. The water-soluble assembly emitted fluorescence in the visible region under the excitation of 980 nm near-infrared light ( Figure 10 c).…”

“… ( a ) The photochromic reaction of Alq 3 complex [ 68 ]; ( b ) the fluorescent quenching mechanism of photoresponsive polymer toward the lanthanide-doped UCNPs [ 69 ]; ( c ) the synthetic route to the hybrid nanoparticles based on photoresponsive compounds; ( d ) the excitation wavelength to trigger the ring-closing and ring-opening reaction of DTE [ 70 ]. …”

Horizontally Oriented Growth of Highly Conductive MoO2 Nanobelts on Sapphire

“…They later achieved the guided growth of millimeter-long GaN nanowires along the nanogrooves of the annealed M-plane (101̅0) sapphire . Up to now, the generality of graphoepitaxial growth has been widely demonstrated in the horizontally oriented growth of various 1D inorganic (e.g., ZnTe, ZnSe, ZnO, CdSe, and CdS) or organic (e.g., metal phthalocyanines, Alq3) nanowires on various substrates (such as SiC, quartz, and spinel). − ,,,− …”

Deterministic Single-Row-Droplet Catalyst Formation for Uniform Growth Integration of High-Density Silicon Nanowires

“…However, as the gaseous precursor feeding in VLS growth tends to produce vertical bundles of standing SiNWs, they need to be collected, transferred and rearranged into precise locations on planar surface for reliable logic device integration . Though many research efforts have been developed to achieve planar growth of VLS SiNWs, , surface faceted groove-guided planar growth, , or postgrowth rearrangement of them, , a scalable integration of orderly VLS-grown SiNWs on planar surface is still missing.…”