Ultra-Bright Thin-Film Light Emitting Devices and Lasers

ended

Thin-film light sources such as OLEDs are extremely valuable, as, in contrast to III-V crystalline LEDs, they can be precisely designed and dimensioned, as single components or in massive arrays, into any target application without the need of hetero-assembly. Unfortunately, their light power density remains about 300 times smaller than that of III-V LEDs. Also, none of today’s thin-film light sources could ever be brought to lasing by electrical pumping. It is the objective of this project to break through the barriers that limit the brightness of thin-film light sources and to achieve lasing by electrical pumping (“injection lasing”) in such sources. Our first target is to create a high-brightness (30W/cm2) thin-film light-emitting device. For the emission layer, we propose a perovskite semiconductor with controlled quantum-confinement features (wells or dots). It will be integrated into a novel light-emitting device, in which electron and hole injection are separately controlled by gates, such that a perfect charge balance is achieved up to the highest current densities. Our next target is to create a thin-film injection laser. We present several innovative strategies to lower the lasing threshold. The emission layer of our light-emitting device will be shaped as a ring resonator with ultra-low optical losses. The gates will be patterned to spatially modulate the carrier injection in the emission layer, which will efficiently restrict the pumping to few selected modes. Further elaborations of cavity designs can lead to mode-locking. Combined with the efficiency of the quantum-confined perovskite emission layer in producing optical gain, these features will reduce the lasing threshold current density to below 100 A/cm2, within reach of our thin-film device. These novel devices will serve numerous applications in the fields of sensing and ICT, by enabling massive optical interconnects, augmented reality displays, on-chip sensing and more.