InAsN quantum dots were grown on GaAs (00 1) substrate by a solid source molecular beam epitaxy (SSMBE) system equipped with a radio-frequency (RF) nitrogen plasma source. The quantum dot formation was confirmed by reflection high-energy electron diffraction (RHEED) observation and atomic force microscopy (AFM) measurement. Dot density as high as similar to1 x 10(11) cm(-2) was achieved. Low-temperature and room-temperature photoluminescence measurements were carried out to investigate the optical property of the quantum dots. Multilayer quantum dot structures were found to shift the photoluminescence emission peak to longer wavelength from 1025 to 1120 nm. (C) 2003 Elsevier B.V. All rights reserved.