A new optical-scanning technique with a spatial resolution of 10 μm has been developed for the observation of surface luminescence. The photoluminescence topographic technique is a fully automated system capable of measuring luminescence intensity from a surface area as large as 25.8 cm3 as well as the actual luminescence spectra from a spot as small as 10 μm in diameter. The system consists of an Ar-ion laser for excitation, a bidirectional scanner with focusing lens, a spectrometer for high spectral resolution, and a photomultiplier for photon counting. Experimental control and data acquisition and display are performed by a Hewlett-Packard 9820A calculator and interface package. Applications of the technique in the analysis of impurity segregation in semiconductor wafers are illustrated.