Measurement of the Distribution Profile of Electroluminescence Cutoff Frequencies over the Area of a Light-Emitting Heterostructure

A hardware–software complex that has no analogues in Russia and abroad and that is designed to measure the distribution of the cutoff frequency of electroluminescence over the area of a light-emitting heterostructure (LHS) is described. The complex provides a spatial resolution of 0.65 µm, an upper measurement limit of 40 MHz, and a relative error of 2%. The electroluminescence cutoff frequency in local areas of an LHS is determined from the decay of the brightness of pixels of LHS images by 1.19 times obtained using a digital CMOS camera with a step-by-step increase in the pulse repetition rate of the LHS-supplying current with an off-duty factor of 2. The complex and the measurement method were tested on commercial green light-emitting diodes. The results of measuring the cutoff-frequency distribution can be used to assess the homogeneity of LHSs.