PURPOSE: To detect the spatial distribution of impurities with high resolution and at high speed by detecting the variation of position of zone and light emission peak by the wavelength deviated from the peak of zone end light emission of a host crystal and thereby correlating it to intensity of light emission.

CONSTITUTION: When a mixed crystal of InGaAs is assumed, In in a GaAs crystal is an impurity atom that brings about changes of band gap depending on the content. A CL ray analysis is made on the sample at a pressing voltage 25KeV in the direction perpendicular to growth stripes at room temperature and obtained the result as shown in the figure. Signals are detected at the wavelength near the peak of zone end light emission and thereabout. According to the result, there is no remarkable variation at 875nm near the peak of light emission. However, periodical variation is observed in the slightly longer wavelength side and the shorter wavelength side, and their relative strength is reversed to each other. This indicates that the observed signal corresponds to spatial variation of concentration of In, and information obtained by said signal corresponds to the original information.