Enhanced DC-Operated Electroluminescence of Forwardly Aligned p/MQW/n InGaN Nanorod LEDs via DC Offset-AC Dielectrophoresis.

Abstract

We introduce an orientation-controlled alignment process of p-GaN/InGaN multiquantum-well/n-GaN (p/MQW/n InGaN) nanorod light-emitting diodes (LEDs) by applying the direct current (DC) offset-alternating current (AC) or pulsed DC electric fields across interdigitated metal electrodes. The as-forwardly aligned p/MQW/n InGaN nanorod LEDs by a pulsed DC dielectrophoresis (DEP) assembly process improve the electroluminescence (EL) intensities by 1.8 times compared to the conventional AC DEP assembly process under DC electric field operation and exhibit an enhanced applied current and EL brightness in the current-voltage and EL intensity-voltage curves, which can be directly used as the fundamental data to construct DC-operated nanorod LED devices, such as LED areal surface lightings, scalable lightings (micrometers to inches) and formable surface lightings. The enhancement in the applied current, the improved EL intensity, and the increased number of forwardly aligned p/MQW/n InGaN nanorods in panchromatic cathodoluminescence images confirm the considerable enhancement of forwardly aligned one-dimensional nanorod LEDs between two opposite electrodes using DC offset-AC or a pulsed DC electric field DEP assembly process. These DC offset-AC or pulsed DC electric field DEP assembly processes suggest that designing for these types of interactions could yield new ways to control the orientation of asymmetric p/MQW/n InGaN diode-type LED nanorods with a relatively low aspect ratio.