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Y.S SYU
INTRODUCTION
EXPERIMENTAL
RESULTS AND DISCUSSION
CONCLUSION
REFERENCES
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So far, in terms of high-brightness applications, efficiency
droop continues to be a major challenge for the InGaN/GaN
blue LED.
Many approaches for suppressing the droop have been
proposed, one of the most common strategies adopted to
reduce electron overflow is the use of a p-AlGaN EBL
between the MQWs and the p-GaN layer.
Unfortunately, the strong polarization field in AlGaN EBL,
including the large piezoelectric and spontaneous polarization
fields, tends to pull down the intensively built conduction
barrier at the LB/EBL interface. Therefore, the electron
overflow can not be suppressed effectively.
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Simultaneously, the polarization-induced band bending and the
valence band offset ΔEv between the LB and the EBL are
considered to inhibit hole injection into the active region.
In this study, we adopt a new EBL structure comprising an Al
component gradient to eliminate the adverse effects of the
notch in the conduction band and the spike in the valence band
at the LB/EBL interface on the performance of LEDs.
ΔEv
The new design of AlGaN EBL is numerically investigated in
the InGaN/GaN blue LEDs via the tailoring of polarization to
improve hole injection efficiency and electron confinement
ability.
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