Field emission from flipped and patterned vertically aligned carbon nanotube arrays

Area of Science:

• Materials Science
• Nanotechnology
• Surface Science

Background:

• Carbon nanotubes (CNTs) exhibit excellent properties for field emission applications.
• High density and poor substrate adhesion are significant limitations for CNT-based devices.
• Vertically aligned carbon nanotube (VACNT) arrays are a promising structure for enhanced field emission.

Purpose of the Study:

• To investigate the field emission properties of patterned VACNT arrays.
• To evaluate the effect of different binders on substrate adhesion and field emission performance.
• To understand the adhesion mechanisms of binders within VACNT structures.

Main Methods:

• Fabrication of patterned VACNT arrays on copper substrates.
• Application of carbon paste and silver epoxy as binders.
• Field emission testing of VACNT arrays.
• Analysis of substrate adhesion and binder migration using energy-dispersive X-ray spectroscopy.

Main Results:

• Field emission was primarily dominated by individual, taller CNTs exceeding the bulk array height.
• Carbon paste demonstrated superior substrate adhesion compared to silver epoxy.
• Energy-dispersive X-ray spectroscopy revealed carbon paste migration into the VACNT bulk volume.
• Silver epoxy did not exhibit significant migration into the VACNT structure.

Conclusions:

• Binder migration into the VACNT volume is crucial for enhancing substrate adhesion.
• Carbon paste's ability to infiltrate the VACNT structure explains its improved adhesion.
• Understanding binder-substrate interactions is key to optimizing VACNT field emission devices.