LED PERFORMANCE

FIG. 3. Color online EQE vs current density of LEDs A, B, and C.

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A>B 5.6%A>C 8.6%at 90A/cm2

LED PERFORMANCE

FIG. 4. Color online Calculated band diagrams of LEDs at 90 A/cm2, aLED A, b LED B, and c LED C. Calculated carrier concentrations ofLEDs at 90 A/cm2, d LED A, e LED B, and f LED C.

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LED PERFORMANCE

TABLE I. Estimated efficiencies of the well near p-GaN in LEDs A, B, and C at 90 A/cm2. A is the Shockley–Read–Hall recombination coefficient (5.4*107 / s), B is the bimolecular recombination coefficient (2.0*10−11 cm3 / s), C is the Auger recombination coefficient (2.0*10−30 cm6 /s), n is the electron concentration, and p is the hole concentration.

n(/cm3)

p(/cm3)

An(/cm3 s)

Bnp(/cm3 s)

Cn2p(/cm3 s)

Efficiency ( %)

LED A 6.69*101

9

6.67*101

9

3.61*102

7

8.92*102

8 5.97*1029 12.9

LED B 6.73*101

9

2.27*101

9

3.63*102

7

3.06*102

8 2.06*1029 12.7

LEDC 6.71*101

9

6.61*101

8

3.62*102

7

8.87*102

7 5.95*1028 12.3

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LED PERFORMANCE

Efficiency=Bnp

An + Bnp + Cn2p

Efficiency =1

+1+An

Bnp

Cn

B

4A is the Shockley–Read–Hall recombination coefficient B is the bimolecular recombination coefficientC is the Auger recombination coefficient

CONCLUSIONS

The suppression of efficiency droop in LEDs without an EBL at high current density is attributed to an increased hole injection efficiency.

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REFERENCES

Sang-Heon Han, Dong-Yul Lee, Sang-Jun Lee, Chu-Young Cho, Min-Ki Kwon,S. P. Lee,1 D. Y. Noh, Dong-Joon Kim, Yong Chun Kim, and Seong-Ju Park, “1Department of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 500-712, Republic of Korea” APPLIED PHYSICS LETTERS 94, 231123 2009

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