Extremely thin InAs/GaAs single quantum well structures have been grown by atomic layer epitaxy. The wells were 2 and 4 InAs monolayers thick. Photoluminescence spectra (19 K) from these structures are sharp, intense, and uniform across the sample with full widths at half‐maximum for the 2 and 4 monolayer wells of 12 and 17 meV, respectively. These results indicate the high degree of control inherent in atomic layer epitaxy as well as its ability to grow high quality materials.