This work reports AlGaN-based deep ultraviolet light-emitting diode (DUV LED) possessing a specifically AlxGa1 − xN / AlyGa1 − yN / AlxGa1 − xN (x > y) structured p-electron blocking layer (p-EBL) to achieve the high external quantum efficiency (EQE). The impact of the p-EBL with AlyGa1 − yN insertion layer at different positions and with different AlN compositions on the hole and electron injection is systematically investigated. Our results show that, for the DUV LED structure in this work, both electrons and holes can be most efficiently injected into the active region by keeping the AlyGa1 − yN insertion layer near to the p-region. The AlN composition for the AlyGa1 − yN insertion layer has also to be optimized for maximizing the carrier injection.
Quantum dots (QDs) with unique properties have evolved to be a key player in the next generation display and lighting applications. Followed by studies on the optimization of QD nanomaterials with low self-absorption properties, we analyze and identify the key parameters of the QDs that impact the color gamut and energy efficiency features of LCD displays using QD-enabled LED backlights, which consist of red and green QDs as well as blue LEDs that act as pumping sources. It is found that both the full width at half maximum (FWHM) and the emission peak positions of the green and the red QDs affect the color gamut. A narrower FWHM for both color QDs is preferred to achieve a wider color gamut while a combination of green QDs with shorter wavelength and red QDs with longer wavelength within the studied wavelength range (520 nm to 540 nm for the green and 610 nm to 635 nm for the red) is also desired. Nevertheless, QD-enabled LED backlight with a combination of longer-wavelength green QDs and shorter-wavelength red QDs is more energy efficient than the reverse case. Therefore, one needs balance these two key factors based on the targeted display performance requirements. On the solid-state lighting application side with QDs, we propose and show a QD-enabled LED light engine architecture that is more energy efficient with high light quality.