Lateral Carrier Diffusion in Ion-Implanted Ultra-Small Blue III-Nitride MicroLEDs.

Ultrasmall micro-light-emitting diodes (μLEDs), sized below 10 μm, are indispensable to create the next-generation augmented and virtual reality (AR/VR) devices. Their high brightness and low power consumption could not only enhance the user experience by providing vivid and lifelike visuals but also extend device longevity. However, a notable challenge emerges: a decrease in efficiency with a reduced size.

Revealing trends and persistent cycles of non-autonomous systems with autonomous operator-theoretic techniques.

An important problem in modern applied science is to characterize the behavior of systems with complex internal dynamics subjected to external forcings. Many existing approaches rely on ensembles to generate information from the external forcings, making them unsuitable to study natural systems where only a single realization is observed. A prominent example is climate dynamics, where an objective identification of signals in the observational record attributable to natural variability and climate change is crucial for making climate projections for the coming decades.

Data assimilation in operator algebras.

We develop an algebraic framework for sequential data assimilation of partially observed dynamical systems. In this framework, Bayesian data assimilation is embedded in a nonabelian operator algebra, which provides a representation of observables by multiplication operators and probability densities by density operators (quantum states). In the algebraic approach, the forecast step of data assimilation is represented by a quantum operation induced by the Koopman operator of the dynamical system.

Hybrid electroluminescent devices composed of (In,Ga)N micro-LEDs and monolayers of transition metal dichalcogenides.

We demonstrate a novel electroluminescence device in which GaN-based μ-LEDs are used to trigger the emission spectra of monolayers of transition metal dichalcogenides, which are deposited directly on the μ-LED surface. A special μ-LED design enables the operation of our structures even within the limit of low temperatures. A device equipped with a selected WSe monolayer flake is shown to act as a stand-alone, electrically driven single-photon source.

Ion implantation of tunnel junction as a method for defining the aperture of III-nitride-based micro-light-emitting diodes.

We report on III-nitride-based micro-light-emitting diodes (µLEDs) operating at 450 nm wavelength with diameters down to 2 µm. Devices with a standard LED structure followed by a tunnel junction were grown by plasma-assisted molecular beam epitaxy. The emission size of µLEDs was defined by shallow He implantation of the tunnel junction region.