We investigate the cause of the optoelectronic performance variations in InGaN/GaN\nmultiple-quantum-well blue light-emitting diodes, using three different samples from an identical\nwafer grown on a c-plane sapphire substrate. Various macroscopic measurements have been\nconducted, revealing that with increasing strain in the quantum wells (QWs), the crystal quality\nimproves with an increasing peak internal quantum efficiency while the droop becomes more severe.\nWe propose to explain these variations using a model where the in-plane local potential fluctuation\nin QWs is considered. Our work is contrasted with prior works in that macroscopic measurements\nare utilized to find clues on the microscopic changes and their impacts on the device performances,\nwhich has been rarely attempted.
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