P.J SYUN
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Outline
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Introduction
Experiment
Results and discussion
Conclusion
References
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Introduction
• In conventional LEDs, strong electrostatic field generated by
the spontaneous and piezoelectric polarization will lead to
severe band-bending, and this deformed conductive band can
aggravate the electrons spill over from the p-type layer.
• In InGaN/GaN quantum wells (QWs) LEDs, holes have a
large effective mass and hence low mobility, which makes it
hard to inject into the MQWs. On the contrary,electronscan
escape from the MQWs easily due to the small effective mass.
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Introduction
• Therefore, a specific design of the quantum barrier next to ptype layer, which is called last quantum barrier (LQB) is
expected to improve the characteristics of LEDs. Some
suggestions, such as a p-doped GaN LQB and the graded
LQB, have been proposed to promote the efficiency.
• Our research found that the devices’ efficiency can be
effectively promoted under high injection current density by
using a p-doped superlattice (SL) LQB with graded indium
mole fraction.
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