- Warsaw-4-PhD School
- Doctoral studies
Bidirectional light-emitting diode dedicated to alternating current operation
Gallium nitride-based light-emitting diodes are the most energy-efficient light sources. Despite their clear advantages, they require a direct current (DC) power supply to operate effectively, while the power grid is built on alternating current (AC). An interesting proposal for a new class of optoelectronic devices dedicated to direct AC operation has been proposed by Mikołaj Żak together with colleagues from the Laboratory of Molecular Beam Epitaxy (NL-14) and other researchers of the Institute of High Pressure Physics PAS (IHPP PAS).
In a paper published in Nature Communications (Impact Factor 16.6), they present a bidirectional light-emitting diode (BD LED) that emits light in both directions of current flow through the device, unlike conventional LEDs, which must be forward biased. It is possible due to the special epitaxial structure of the BD LED, in which the active region is surrounded on both sides by tunnel junctions from the p-type doped regions. This ensures that electrons and holes are effectively injected into the same quantum well above the turn-on voltages under both negative and positive bias.
The paper "Bidirectional light-emitting diode as a visible light source driven by alternating current" (M. Żak, et al. Nat Commun 14, 7562 (2023)) is an important part of the upcoming PhD thesis of M.Sc. Mikołaj Żak and is the result of many years of research on tunnel junctions in GaN undertaken by the NL-14 group of IHPP PAS.