Haynes-Shockley Experiment

The diffusion equation for minority electrons in a semiconductor is,

$\large \frac{\partial n}{\partial t}= D\nabla^2n +G+\frac{n-n_0}{\tau}$.

If the generation term $G$ is pulsed on for a short time at $t=0$ and $x=0$, the solution is,

$\large n-n_0=\frac{\exp\left(\frac{-(r-\mu Et)^2}{4Dt}\right)\exp\left(\frac{-t}{\tau}\right)}{\sqrt{4\pi Dt}}$.

The form below plots a cross section of the minority electron concentration for various parameters. This is what is measured in a Haynes-Shockley experiment.


$x$ at $t=0.01$

τ =


E =


μ =

[cm²/V s]