Nanocrystalline silicon superlattices: building blocks for quantum device

A nanocrystalline silicon superlattice (nc-Si SLs) is a structure consistin g of Si nanocrystal layers separated by nanometer-thick SiO2. A long range order in the nc-Si SL is obtained along the direction of growth by periodic ally alternating layers of Si nanocrystals and SiO2. A number of characteri zation techniques such as transmission electron microscopy (TEM) and atomic force microscopy (AFM), Auger elemental microanalysis. X-ray diffraction a nd X-ray small angle reflection have proved that the nc-Si SL exhibits a ve ry narrow nanocrystal size distribution (less than 5% in average) and very abrupt and flat nc-Si/SiO2 interfaces with a roughness of < 4 Angstrom. Con ductance tunnel spectroscopy and capacitance-voltage (C-V) measurements sho wed that the nc-Si SL is a nearly defect free structure. The results hold p romise for nc-Si SL quantum device applications. (C) 2000 Elsevier Science S.A. All rights reserved.