Integration of low dimensional crystalline Si into functional epitaxial oxides for next generation solar cell application

Si quantum dots (QD) embedded into Gd₂O₃ and Si quantum wells (QW) with epitaxial Gd₂O₃ as the barrier layers were grown on Si substrates. With decreasing dot size down to the 2-nm range, the optical absorption exhibits a spectacular shift in spectral threshold upto 2.9plusmn0.1 eV, as compared to the 1.12 eV absorption edge of the bulk Si crystal. Such shift suggests a significant influence of quantum confinement on the nanocrystal/oxide interface band diagram; the effect of which was observed to be predominantly caused by the upshift of the nanocrystal conduction band. Also, the Pt/Gd₂O₃/Si MOS capacitors comprised with Si nanoclusters display large hysteresis (~1.5-2 V) in capacitance-voltage measurements making them potential candidate of nonvolatile memory devices.