Heat Dissipation in Flexible Nitride Nanowire Light-Emitting Diodes

Abstract

We analyze the thermal behavior of a flexible nanowire (NW) light-emitting diode (LED) operated under different injection conditions. The LED is based on metal–organic vapor-phase deposition (MOCVD)-grown self-assembled InGaN/GaN NWs in a polydimethylsiloxane (PDMS) matrix. Despite the poor thermal conductivity of the polymer, active nitride NWs effectively dissipate heat to the substrate. Therefore, the flexible LED mounted on a copper heat sink can operate under high injection without significant overheating, while the device mounted on a plastic holder showed a 25% higher temperature for the same injected current. The efficiency of the heat dissipation by nitride NWs was further confirmed with finite-element modeling of the temperature distribution in a NW/polymer composite membrane.

Red GaPAs/GaP Nanowire-Based Flexible Light-Emitting Diodes

“…The flexible LED operation current density was roughly estimated at 50 A/cm 2 (4 nA/NW), i.e., 5 times lower than for the LEDs-on-Si. It should be noted that for a stable LED operation the current density value at 5-10 A/cm 2 is preferable since small diameter GaPAs/GaP NWs embedded into a PDMS membrane can suffer overheat problems due to the low heat capacity of small diameter NWs and bad thermal conductivity of the PDMS matrix, and the Joule heating can destroy NWs [50]. To achieve the improved performance, flexible LEDs based on GaPAs/GaP NW/PDMS membranes require further development of both work current density decreasing and improved heat evacuation.…”

Optimized method of thermoelectric cooler-based thermal management for improving the luminous efficacy of light-emitting diodes

“…Some of the results of heat problems are causing thermal decay for luminous flux and shortening the lifetimes; even overheating can cause damage to the mechanical, physical, and chemical properties of the structure of the device [6][7]. Thus, the target of reducing the effect of heat has attracted a lot of attention from researchers and engineers to propose solutions for thermal management effectively [8][9][10][11]. Among those solutions, a thermoelectric cooler (TEC) based thermal management is a potential solution to improve the performance of LED devices because of the quick cooling performance [12][13].…”