Diffusion of holes and electrons

By Saumitra Raj Mehrotra1, Gerhard Klimeck1

1. Purdue University



Published on


Diffusion is a process of particles distributing themselves from regions of high- to low- concentrations. In semi-classical electronics these particles are the charge carriers (electrons and holes). The rate at which a carrier can diffuse is called diffusion constant with units of cm2/s.

Diffusion of holes and electrons

The image shows the process of steady state diffusion in an intrinsic semiconductor bar with different light shining intensity (different carrier generations rates /cm3) at the center of the bar. In general electrons have a higher rate of diffusion than holes. As more electron-hole pairs are generated, fewer excess electrons remain, diffusing away faster as compared to holes.


Image rendered using nanoHUB tool Drift Diffusion Lab (http://nanohub.org/tools/semi)

Cite this work

Researchers should cite this work as follows:

  • Saumitra Raj Mehrotra, Gerhard Klimeck (2010), "Diffusion of holes and electrons," http://nanohub.org/resources/8820.

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