Patterned growth of carbon nanotubes over vertically aligned silicon nanowire bundles for achieving uniform field emission

Abstract

A fabrication strategy is proposed to enable precise coverage of as-grown carbon nanotube (CNT) mats atop vertically aligned silicon nanowire (VA-SiNW) bundles in order to realize a uniform bundle array of CNT-SiNW heterojunctions over a large sample area. No obvious electrical degradation of as-fabricated SiNWs is observed according to the measured current-voltage characteristic of a two-terminal single-nanowire device. Bundle arrangement of CNT-SiNW heterojunctions is optimized to relax the electrostatic screening effect and to maximize the field enhancement factor. As a result, superior field emission performance and relatively stable emission current over 12 h is obtained. A bright and uniform fluorescent radiation is observed from CNT-SiNW-based field emitters regardless of its bundle periodicity, verifying the existence of high-density and efficient field emitters on the proposed CNT-SiNW bundle arrays.

High Current Emission from Patterned Aligned Carbon Nanotubes Fabricated by Plasma-Enhanced Chemical Vapor Deposition

“…However, the turn-on field of CNT grown with H 2 /C 2 H 2  = 140/5 sccm is lower than the CNT grown with 180/10; they had similar enhancement factor. The same phenomenon was also appeared in other works [26, 28]. The field enhancement factor β is strongly dependent on the geometrical shape of the CNTs.…”

“…The maximum current density of the CNTs could reach 70 mA/cm 2 (Fig. 5b) with testing repeatedly which was higher than other reported works [26–28]. Fluctuation and drastic drop did not happen at higher applied voltages which indicated the CNTs had a good contact with the substrate and high-voltage endurance.…”

“…In this work, the CNT emitters were fabricated using radio frequency plasma-enhanced chemical vapor deposition (PECVD) method on patterned Si substrate. The vertically aligned CNT arrays showed good field emission properties with high emission current and ultra-long-term emission stability which were better than other reported patterned vertical CNTs [26–28]. …”

Study of field emission properties of pure graphene-CNT heterostructures connected via seamless interface

“…Thus it will be decisive to investigate the field emission performance of pure graphene/ CNT seamless heterostructures without the interference of any oxide material or polymer matrix as well as the absence of metal electrodes at the bottom. In addition, in order to design a field emission device made of vertical CNTs, it is desirable for the device to be pattern oriented to avoid overall film resistance originating due to the screening effect [27,28].…”