Light-Emitting Diodes9 Videos

LED02 – Carrier Transport in Multi Colour Deep Ultraviolet Light Emitting Diodes

Hofmann G., Höpfner J., Schilling M., Muhin A., Römer F., Wernicke T., Kneissl M., Witzigmann B.

Deep ultraviolet (DUV) light emitting diodes (LEDs) and lasers are enabled by high band gap Aluminium Gallium Nitride (AlGaN). The efficiency of recent multi quantum well (MQW) DUV emitters is still in the percent range which can be in part attributed to the hole injection. The hole injection and the carrier distribution in the high […]

LED04 – Development of time-dependent Exciton diffusion solver for modeling Triplet-Triplet Fusion Mechanism in OLEDs

Huang J.-Y., Hung H.-C., Hsu K.-C., Chen C.-H., Lee P.-H., Lin H.-Y., Lin B.-Y., Leung M.-K., Chiu T.-L., Lee J.-H., Wu Y.-R.

In this work, we developed a both stable and time-dependent exciton diffusion model including singlet and triplet exciton coupled with a modified Poisson & drift-diffusion solver to demonstrate the mechanism of triplet-triplet fusion (TTF) OLEDs. Using this modified simulator, we can demonstrate the characteristics of OLEDs including current-voltage curve, quantum efficiency performance, time-resolved electroluminescence spectrum, […]

LED06 – Ray Tracing Simulation of a GaN-based integrated LED-Photodetector System

Amiri P., Casals O., Auf der Maur M., Prades J. D.

An optical sensor system consisting of a pair of GaN LED and Photodetector (PD) is simulated using COMSOL Multiphysics, and the possibility of using this system as absorption coefficient sensor is studied. By locating both LED and PD on a same substrate and measuring transmitted power to the PD, it would be possible to sense […]

LED09 – Enhanced optoelectronic properties of UV-C light-emitting diode

We numerically analyzed proposed structure named as LED S2 in comparison to reference structure LED S1. In LED S2 we introduced undoped AlGaN and p-AlGaN layers between the electron blocking layer (EBL) and the p-GaN (hole injecting layer). The simulation finding shows proposed structure (LED S2) provide a better strategy for lowering electron overflow and […]

LED03 – RGB LED active region design and optimization with Genetic Evolution Algorithm

Mamedov D. V., Kisin M. V., Chuang C.-L., El-Ghoroury H. S.

Multi-quantum-well (MQW) LED is a complex distributed system with strong interaction between two opposite carrier flows, electrons and holes. For both types of carriers, the carrier injection into each QW depends on transport conditions across the whole active region (AR) and is affected by capture-recombination balance in all active QWs. Multi-color LEDs with different types […]

LED08 – Influence of Prestrained Graded InGaN interlayer on the Optical Characteristics of InGaN/GaN MQW-based LEDs

In this work, an InGaN/GaN multi-quantum well light emitting diode is designed with different kinds of prestrain layers (InGaN) inserted between the active region and n-GaN layer to demonstrate the effects of piezoelectric polarization on GaN-based LEDs. The device describes a GaN buffer layer which promotes charge injection by minimizing energy barrier between electrode and […]

LED05 – Reliable prediction of the singlet-triplet gap in TADF molecules with GW/BSE approach

Chaudhuri D., Patterson C. H.

Organic light emitting diode (OLED) molecules that exhibit thermally activated delayed fluorescence (TADF) have emerged as a promising technology for various lighting and display applications. Such systems depend on low singlet-triplet gaps of the order of kT to allow reverse inter-system crossing. Here, we demonstrate the capability of a GW/BSE method to predict excitation energies […]

LED01 – First-principles computation of charge-carrier recombination coefficients in optoelectronic materials

Zhang X.

Charge-carrier recombination plays a decisive role in determining the efficiency of optoelectronic materials and devices, but their accurate experimental measurements and interpretation are challenging. In this context, first-principles computation of charge-carrier recombination coefficients is particularly useful. It allows not only rigorous computation of the recombination rates, but also intuitive interpretation of the microscopic recombination mechanisms […]

LED07 – Effect of Parabolic Quantum Well on Internal Quantum Efficiency of InGaN/GaN based MicroLED at low current density

Gurjar R., Prakash Singh C., Singh Meena A., Ghosh K.

The quantum cascade stark effect (QCSE) in rectangular shaped quantum well (QW) poses a hindrance to increase the internal quantum efficiency (IQE) of nitride based LEDs. To circumvent the said problem for micro-LEDs operating at low current density, a parabolic QW structure has been proposed which is found to be useful to alleviate the QCSE […]