Carrier Diffusion, Generation and Recombination in Semiconductor Devices
Understanding how diffusion, generation and recombination drive charge transport in a semiconductor.
This article is part of The Joy of Semiconductor Devices series — a collection of posts that explains the inner workings of semiconductor technology from first principles in an accessible manner.
Here are the previous posts in this series if you need to refer back to the concepts used in this article:
Earlier, we looked at how electrons drift in a semiconductor when an electric field is applied to it. Today, we will look at another mechanism of charge transport called carrier diffusion, discuss generation and recombination, and bring it all together with the continuity equation.
Here is what we will cover:
Mechanism of Carrier Diffusion: How charged particles in a semiconductor move due to diffusion.
Diffusivity and the Diffusion Equation: Understanding the factors that control the flow of diffusion current.
Current Density: Calculating electron and hole current densities due to drift and diffusion.
Generation and Recombination Processes: Generation and annihilation of electron-hole pairs and its relation to the energy band diagram.
The Continuity Equation: The expression that ties the different charge transport mechanisms together.
Read time: 10 mins
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