High-brightness scaled perovskite light-emitting devices towards injection lasing
Perovskite semiconductors hold large promise for optoelectronic applications such as solar cells and light-emitting diodes (LEDs). In just a few years of research, perovskite LEDs have reached an external quantum efficiency of about 20%, almost at par with incumbent technologies. Scaling down of perovskite devices hinges on patterning technology. Patterning by photolithography will be studied. Scaled-down LED stacks and devices will be designed, processed, and characterized optically and electrically. The downscaling study will allow to conclude on the possible occurrence of parasitic recombination pathways at etched sides. As the target is high-brightness devices, considerable attention will be spent on the interfaces of the perovskite semiconductor with hole injection and electron injection layers. Inorganic injection layers will be proposed, which are likely able to sustain higher thermal stress and higher robustness at high injection currents. In terms of the perovskite active layers, several types of perovskites will be compared: organic, inorganic, and hybrids. Characterization of the devices with PL and EL, including with pulsed bias, will be carried out, and lead to conclusions as to the optimum stack and materials. With the knowledge on patterning, waveguide structures will be processed in parallel to the LED device study above. They will be used for optical pumping experiments. They will evolve from simple stacks to gradually incorporating more elements of full LED devices, including contacts. In the final part, gated light-emitting diodes with extremely low optical losses will be proposed, designed, and processed using the know-how build up in the first part. The goal is to achieve an electrically pumped laser with such structures.