In this paper, we will demonstrate a novel approach to incorporate Si and/or Ge nanostructures into crystalline rare earth oxides using molecular beam epitaxy (MBE) for nanoelectronic devices application. By efficiently exploiting the growth kinetics during MBE we succeeded in creating semiconductor nanostructures exhibiting various dimensions, ranging from three dimensionally confined quantum dots (QDs) to the quantum wells, where the particles are confined in one dimension. The crystalline rare earth oxide that has been used in this study is the epitaxial gadolinium oxide (Gd2O3). The monolithic heterostructures comprised of Gd2O3-Ge/Si- Gd2O3 grown on Si substrate exhibit excellent crystalline quality with atomically sharp interface. The room temperature capacitance-voltage measurements performed on a metal oxide semiconductor (MOS) structure with embedded Si, Ge and Si(1-x)Gex QDs into oxide exhibit the electron storage density of 8*1012 cm -2, correspond to two electron per quantum dot and large retention time (>105sec) exhibiting its potential in future nonvolatile memory devices. In addition, silicon quantum dots imbedded in lattice-matched Gd2O3 matrix exhibit large size-dependent bandgap widening. Measurements of photocharging spectra of these crystals indicate only marginal variation of the photoionization threshold energy. The latter suggests that most of the confinement-induced bandgap width variation is caused by the upward shift of the Si nanocrystal (QDs) conduction band bottom. © 2009 IEEE.