Has a low luminescence efficiency and its surface readily deteriorates by electron or photon excitation at the power levels generally required to perform spatially resolved cathodoluminescence (CL) or photoluminescence scanning. Previous CL studies employed a sophisticated mirror system to provide the necessary collection efficiency to image defects in . In this paper, we demonstrate a simple high collection efficiency CL technique using a solid‐state photodiode within the sample chamber of a scanning electron microscope. A comparison is made of the patterns formed by the CL dark spots and the etch features produced by a known defect etchant.