Exciton Bohr radius
= Exciton Bohr radius
{title2=$a_X=4\pi\epsilon_0\epsilon_r\hbar^2/(\mu^*e^2)$}
The characteristic relative-motion length of a hydrogenic <Wannier-Mott exciton>, with dielectric screening and <exciton reduced mass> $\mu^*$. Comparing a <quantum dot>'s dimensions with this scale helps distinguish strong carrier confinement from confinement of a comparatively intact bound pair.