A multiscale quantum mechanics/electromagnetics method for device simulations.

Area of Science:

• Computational physics and chemistry
• Materials science and engineering
• Microelectronics and nanotechnology

Background:

• Multiscale modeling is crucial for diverse research fields like materials science, microelectronics, and biology.
• Existing methods often struggle to bridge quantum mechanical phenomena with macroscopic electromagnetic environments.

Purpose of the Study:

• To introduce and validate a novel multiscale computational method integrating quantum mechanics (QM) with classical electromagnetics (EM).
• To demonstrate the QM/EM method's capability in simulating complex electronic devices and systems.

Main Methods:

• The quantum mechanics/electromagnetics (QM/EM) method treats electron scattering regions quantum mechanically and the surroundings classically using Maxwell's equations and drift-diffusion models.
• QM and EM models are solved self-consistently, using interface potential distributions and current densities as boundary conditions.
• The method was applied to junctionless field-effect transistors, tandem photovoltaic cells, and carbon nanotube-based molecular devices.

Main Results:

• Simulations of junctionless field-effect transistors showed good agreement with experimental transfer characteristics.
• Optical properties of a tandem photovoltaic cell were studied, revealing coupling between multiple QM regions via the EM model.
• The QM/EM method demonstrated accuracy and efficiency in simulating a carbon nanotube molecular device.

Conclusions:

• The developed QM/EM method offers a powerful and versatile tool for multiscale modeling of electronic devices.
• This approach accurately captures the interplay between quantum mechanical effects and the electromagnetic environment.
• The QM/EM method shows significant potential for advancing research in materials science, microelectronics, and molecular devices.