Unusually strong space-charge-limited current in thin wires

TL;DR

This paper reveals that the nonlinear current-voltage behavior in thin wires is primarily due to enhanced space-charge-limited current caused by poor screening in high aspect ratio materials, supported by experiments and theory.

Contribution

It introduces a new understanding of space-charge-limited current in thin wires, emphasizing the role of aspect ratio and screening effects, supported by experimental data and theoretical modeling.

Findings

Nonlinear I-V characteristics are due to space-charge effects, not Schottky barriers.

Poor screening in high aspect ratio wires dramatically increases space-charge-limited current.

New scaling laws relate current to aspect ratio in thin wires.

Abstract

The current-voltage characteristics of thin wires are often observed to be nonlinear, and this behavior has been ascribed to Schottky barriers at the contacts. We present electronic transport measurements on GaN nanorods and demonstrate that the nonlinear behavior originates instead from space-charge-limited current. A theory of space-charge-limited current in thin wires corroborates the experiments, and shows that poor screening in high aspect ratio materials leads to a dramatic enhancement of space-charge limited current, resulting in new scaling in terms of the aspect ratio.