Gas discharge during degradation of indicating light-emitting diodes based on InGaN/GaN heterostructures in a polymer case

A gas discharge is observed in light-emitting diodes based on an InGaN/GaN structure for currents significantly greater than the operating currents, under conditions of considerable self-heating with formation of blisters in the polymer case of the LED, localized above the emitting surface of the heterostructure. In this case, we detected threshold appearance of intense emission in the red and infrared ranges of the spectrum. We show that the major mechanism for this emission is formation of a gas-discharge plasma as a result of non-oxidative thermal degradation of the polymer, surrounding the heterostructure and current carrying contacts.