Tauc Plot - Determining Optical Band Gap

This page was developed by the Queen's University Applied Sustainability Research Group.

A Tauc plot is one method of determining the optical band gap in semiconductors. The square root of the product of the absorption coefficient and photon energy -(aE)^0.5 - is plotted versus photon energy. The curve should have a section of straight line. If extended to the x-axis, the x-intercept of this line gives the optical band gap.

Source: https://ascg.msm.cam.ac.uk/characterisation/uvvis.php