Enhancing deep-UV emission at 234 nm by introducing a truncated pyramid AlN/GaN nanostructure with fine-tuned multiple facets

Application of patterned sapphire substrate for III-nitride light-emitting diodes

Recent decades have witnessed flourishing prosperity of III-nitride emitters in solid-state lighting and high-resolution displays. As one of the widely used substrates, sapphire shows superiority for heteroepitaxial growth of III-nitride light-emitting diode (LED) structure, due to the advantages of stability, low cost, high mechanical strength, as well as mature fabrication technology. However, realization of efficient LEDs grown on sapphire substrate is impeded by high density of defects in epilayers and low light extraction efficiency. The emergence of patterned sapphire substrate (PSS) turns out to be a promising and effective technology to overcome these problems and enhance the LED performances. In this review, we first introduce the background and recent advances of PSS applied in III-nitride visible and ultraviolet LEDs are. Then, we summarize the fabrication methods of PSS, together with novel methods to define nanometre-scale patterned structures. We further demonstrate the effect of PSS that contributes to reduce the threading dislocation density (TDD) of epilayers in detail. Meanwhile, mechanism of light extraction efficiency enhancement by adopting PSS is presented based on numerical analysis. Next, we explore the influence of PSS structural parameters (e.g. pattern size, pattern shape and aspect ratio) on LED performances, spanning from visible to deep ultraviolet UV emission region. Finally, challenges and potential prospects in PSS for future LED development are proposed and forecasted as well.

Interfacial modulation and plasmonic effect mediated high-brightness green light sources in a single Ga-doped ZnO microwire based heterojunction

Heterostructure manufacturing has been extensively studied as indispensable footstones in the progressive semiconductor optoelectronic devices due to their constituent materials, interfacial states and electronic transport capabilities, thus enabling competitive candidates...