Terahertz Schottky Barrier Diodes Based on Aligned Carbon Nanotube Arrays

Carbon nanotubes (CNTs) with superior electrical characteristics are among the most promising candidate materials for constructing millimeter wave and terahertz wave electronic devices. However, the reported Schottky barrier diodes (SBDs) based on CNTs usually exhibited high series resistance and severe mismatch to lower impedance external circuits, which limits the devices for high frequency applications. In this work, CNT SBDs of lateral structure with a rectify current density of -0.78 mA/
$\mu \text{m}$
and a short circuit current responsivity of 6.8 A/W are demonstrated based on aligned carbon nanotube arrays (A-CNTs) with high-density and high-semiconducting purity on a quartz substrate. The A-CNT SBD with a width of
$10 \mu \text{m}$
and an
$\text{L}_{\text {ch}}$
of 50 nm under zero bias exhibits an ultra-low intrinsic capacitance of 2.5 fF and an intrinsic cutoff frequency
${f}_{\text {C}}$
of up to 840 GHz, which suggests that CNT-based SBDs are promising for millimeter wave and terahertz wave applications.