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V-defect
1.46 V
Defect-free
1.71 V
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Conclusion
•
In summary, combining results of I-V curves, SEM, TEM, and C-AFM
measurements, we have studied the features of V-defect and its formation
mechanism, and shown significant effects of V-defects on the electrical and
optical characteristics of InGaN MQW LEDs.
•
It is found that the density and size of V-defects increase as the period number of
QWs increases from three to five.
•
Besides, it is proposed that LEDs with averagely larger size and higher density of
V-defects will suffer a larger leakage current.
•
Furthermore, EL characteristics of LEDs will also be deteriorated since carriers are
preferentially captured to V-defects and associated TD lines to recombine
nonradiative as shown by C-AFM measurements.
•
Therefore, it is important to reduce the total fractional area of V-defects by
optimizing structural parameters and growth conditions.
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