  We study the photoluminescence spectra of n-doped InP bulk wafers, both in
the reflection and the transmission geometries relative to the excitation beam.
From the observed spectra we estimate the spatial distribution of minority
carriers allowing for the spectral filtering due to re-absorption of
luminescence in the wafer. This distribution unambiguously demonstrates a
non-exponential drop-off with distance from the excitation region. Such a
behavior evidences an anomalous photon-assisted transport of minority carriers
enhanced owing to the high quantum efficiency of emission. It is shown that the
transport conforms very well to the so-called Levy-flights process
corresponding to a peculiar random walk that does not reduce to diffusion. The
index gamma of the Levy flights distribution is found to be in the range gamma
= 0.64 to 0.79, depending on the doping. Thus, we propose the high-efficiency
direct-gap semiconductors as a remarkable laboratory system for studying the
anomalous transport.
