Thermal Effects in a Bendable InGaN/GaN Quantum-Well Light-Emitting Diode

The fabrication of a bendable light-emitting diode (BLED) and the comparison of its performance with that of a vertical light-emitting diode (VLED) are shown. In particular, the difference in their thermal responses is investigated. Before it is overheated, the BLED has higher output intensity, when compared with the VLED, particularly when the duty cycle of current injection is large. This result is attributed to the larger thermal expansion of the attached metal layer for applying a strong tensile strain to the nitride epitaxial layer in current-induced heating of the BLED such that the quantum-confined Stark effect in its quantum-well layers is reduced. Such a tensile strain is weaker in the VLED because of the moderation of the wafer-bonded Si substrate.