Using high resolution electron beam lithography and reactive ion etching, wires of GaAs/GaAlAs-quantum wells have been fabricated with widths between 5 μm and 0.5 μm. We have investigated the recombination luminescence of the charge carriers in time-resolved spectroscopy as a function of the wire width. We find a strong reduction of the recombination lifetime and a corresponding quenching of the luminescence intensity with decreasing wire width. This can be explained assuming nonradiative recombination via surface-levels as a very fast recombination mechanism. With a simple model we are able to describe the observed behaviour and obtain values for the surface-recombination velocity of about 3×105 cm/s. © 1989.