Research on the property of Micro LED with different chip shapes

Micro LED has a wide range of application prospects due to the advantages of high brightness, high contrast and long life. In this paper, square shape Micro LED with the side length of 30-100μm and corresponding circular shape Micro LED were designed and fabricated. The electrical, optical and thermal characteristics of micro LEDs with the same light-emitting area and different chip shapes are comparatively studied. The results show that the forward voltage and series resistance of square and circular Micro LEDs are approximately. The change of chip shape does not affect the luminous flux. The radiant flux of square and circular Micro LED is approximately at low current density. However, at a higher current density, the radiation flux of the square Micro LED with a size of 60μm or more is larger than that of the circular Micro LED, and the peak radiant fluxes of 80μm, 100μm are 7.4%, 3.3% higher than that of the circular chip. This is because the side area of the square chip is about 12.8% larger than that of the circular chip, resulting in more photons overlapping from the side surface. The measured temperature coefficient and the junction temperature at 20mA of square and circular chips are also approximately.