  We study the photoluminescence spectra excited at an edge side of n-InP slabs
and observed from the broadside. In a moderately doped sample the intensity
drops off as a power-law function of the distance from the excitation - up to
several millimeters - with no change in the spectral shape.The hole
distribution is described by a stationary Levy-flight process over more than
two orders of magnitude in both the distance and hole concentration. For
heavily-doped samples, the power law is truncated by free-carrier absorption.
Our experiments are near-perfectly described by the Biberman-Holstein transport
equation with parameters found from independent optical experiments.
