TECHNOLOGY AND PHOTOLUMINESCENCE OF GAAS MICROCRYSTALLITES AND NANOCRYSTALLITES

A new method for the production and separation of semiconductor micro- and nanocrystallites is reported. We obtain suspensions with crystallites in a size range from several micrometers down to tens of nanometers by wet micromilling of monocrystalline bulk material. Gradient sedimentation and centrifugation are applied to extract fractions containing particles of a narrow size distribution. Photoluminescence spectra of GaAs microcrystallites deposited on Si substrates show a size dependent, unexpectedly strong blue-shift of up to 30 meV. We discuss the observed shift on the basis of surface stress and quantum confinement. © 1992.