Silicon & III–V semiconductor device simulation

Silicon and III–V semiconductor device simulation is the modelling of crystalline semiconductor devices using coupled electrostatics, carrier transport and recombination. In OghmaNano, these systems are solved using drift–diffusion models that capture how electrons, holes and electric fields evolve through a device under bias and illumination.

Silicon provides the cleanest and most familiar reference system: PN junctions, depletion regions, drift and diffusion currents and well-understood recombination pathways. III–V materials such as GaAs extend this framework to compound semiconductors with different band structures, mobilities and recombination behaviour, but the same underlying physics.

This chapter brings these systems together. The goal is not to treat silicon and III–V devices as unrelated examples, but to show that they are solved within a single physical and numerical framework. Once this is understood, the same approach can be extended to more complex systems such as perovskite and organic devices.

1. Silicon device tutorials

Silicon tutorials provide the cleanest entry point into semiconductor device modelling. They illustrate how doping, contacts, recombination and electrostatics interact to produce the measured electrical response.

• Silicon PN Junction Diode — fundamental drift–diffusion simulation of a rectifying junction.
• Polycrystalline silicon solar cell — industrial-style photovoltaic device simulation.
• Amorphous silicon solar cell — thin-film device with defect-limited transport.
• Si 2D NMOS capacitor — electrostatics, depletion and field control in semiconductor structures.

2. III–V semiconductor devices

III–V semiconductors such as GaAs demonstrate that the same drift–diffusion framework applies beyond silicon. Changing material parameters and geometry allows the simulation of compound semiconductor devices without changing the underlying solver.

• GaAs PN Junction Diode
• GaAs 3D drift–diffusion with a vertical defect

3. Underlying physics

These simulations are based on drift–diffusion transport coupled to Poisson’s equation. The model solves how carrier density, electrostatic potential and recombination evolve self-consistently. This is the foundation of physically based semiconductor device simulation.

• Drift–diffusion theory
• Shockley–Read–Hall recombination
• Charge carrier mobility

4. Where should you start?

Start with the silicon PN junction diode if you are new to device simulation. It provides the simplest route to understanding drift–diffusion modelling. Then move to solar cells or MOS structures depending on your application, and finally to III–V devices to generalise the approach.