Thermal Behavior and Infrared Properties of the Vertical-Electrode GaN LED

摘要

The thermal and infrared properties of a vertical-electrode gallium-nitride light-emitting diode (GaN LED) are studied.Because infrared emissivity is a critical parameter for temperature measurements, the relationship between temperature and emissivity for a vertical-electrode GaN LED is investigated using different heating mechanisms; the result indicates a strong dependence between them. The temperature variation across the chip surface of a LED with a Si substrate increases from 2.9 to 8.4℃ when the current changes from 100 to 900 mA with heat sink temperature of 45℃. Temperature nonuniformity may occur as a consequence of nonuniform joule heating, which is due to nonuniform current flow through the vertical-electrode LED. Around the electrode pad the spreading current is especially crowded.