Enhance the Electron Injection Efficiency for DUV LEDs
The unbalanced carrier injection for DUV LEDs illustrates that the electron tends to overflow from the active region. The underly mechanism arises from three aspects: (1) electrons cannot be consumed by forming electron-hole pairs and recombine radiatively in the active region, which is due to the insufficient hole injection, (2) the electron have larger mobility and are more mobile, (3) The conduction band offset between the AlGaN based quantum barrier and quantum well decreases, which correspondingly reduces the conduction band barrier height, enabling the active region to lose the effective confinement capability for electrons. In this chapter, we propose different methods for increasing the electron injection efficiency, and specifically, we demonstrate novel designs to reduce the electron drift velocity and hence the energy, so that the quantum wells have more chances of capturing the electrons.
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