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Harold

The Hetero-structure Laser Diode Model

Harold

Quantum Dot Simulations

Include Multiple Quantum Dot Layers in Laser Simulations

Coming Early 2025

In early 2025 we’re bringing Nobel Prize winning topic of Quantum Dots to our software Harold. The quantum dot model will allow users to compute absorption and gain spectra for quantum-dot based lasers and SOAs thanks to its 3D strain model and 3D band structure calculator.

Test your dot designs are delivering the high-temperature performance that quantum-dot materials are promising the World.

Key Features

8 Band 3D k.p Model

Identify the available energy states in the conduction and valence band with our spurious free 8-band model for an individual quantum dot.
The band gap energy is perturbed by the coupling to the light hole, heavy hole, and spin orbital bands. By simulating these further bands, our 8-band K.P model will more accurately describe the band gap and the gain spectra results.

Full 3D Strain Model

The strain due to lattice mismatch between materials can have a significant effect on a quantum dot’s energy levels. Our continuous mechanical strain model rises to the challenge of calculating the full 3D strain tensor necessary for describe a 3D quantum dot’s geometry (apposed to the 1D stain from a quantum well). This allows for a detailed description of confining potential and a more accurate description of the system.

Distribution of Dot Sizes

When fabricated, quantum dots don’t have the intended singular size but a distribution of sizes to detrimental effect to properties such as linewidth. To account for this, Harold will simulate a Gaussian distribution of dot sizes and combine the results in its final output. This gives a more accurate reflection of the results that can be expected at fabrication.

Developed with Leading Research Groups

The Harold Quantum Dot Model has been developed in collaboration with Cardiff University - one of the UK’s leading centers for compound semiconductor photonics research. In the figures shown we demonstrate the excellent agreement between the results of the model and experimental data measured by Cardiff. The devices were fabricated by the University College of London.

The simulation results and experimental data show excellent agreement at this stage. These simulations have had their dot size and distribution calibrated to the experimental data, giving insight to the size and consistency of the fabrated dots.