Changes in properties of GaN blue light-emitting diodes over time

Electrical conduction tests of metal-insulator-semiconductor(MIS)-structure GaN blue light-emitting diodes have been performed. Samples in which the emission intensity improved over time and samples in which the emission intensity degraded with time were observed. The pattern of change in both types was studied by measuring the device properties. Degradation of emission intensity was seen to be caused by changes in the emission and electron injection mechanism. Reference was made to the action of Zn in the I-S region.