Electrical properties of MIS structures with silicon nanoclusters
The theoretical and experimental investigations of electrical properties of the Al-SiO2- -SiO ( ncs Si − 2-Si structures grown using high temperature annealing SiOx, x < 2, have been carried out. It has been experimentally found that the Al-SiO2- ( ) ncs Si − -SiO2-Si structures with the tunnel dielectric layer revealed the effect of dynamic memory. Electric properties and parameters of the interface states located between and SiO ncs Si− 2 were studied in detail by measuring of current-voltage, capacitance-voltage, and thermally stimulated current characteristics.
NeoSilicon materials and silicon nanodevices
We propose a novel material NeoSilicon, in which both particle size and interparticle distance of nanocrystalline silicon (nc-Si) quantum dots are precisely controlled. New functions in electron transport, photon emission and electron emission are expected due to quantum effects at room temperature and large interaction between dots. The bandgap is determined by the particle size. The conductivity is controlled mainly by tunneling processes. The transport characteristics are also controlled by charge quantization effect. We present fabrication and characterization of NeoSilicon. Based on the idea of separation of the nucleation and the growth processes in plasma decomposition of silane, we have successfully prepared nc-Si particles of 8 nm in diameter with size dispersion of 1 nm, whose surfaces are covered by naturally formed oxide of 1.5 nm thickness. Further reduction of dot size is achieved to 4 nm using self-limiting oxidation processes. Single electron transport characteristics of nc-Si are demonstrated in both planar and vertical transistor structures. Highly efficient electron emission is observed in NeoSilicon samples. Photoluminescence intensity enhancement due to no-phonon-assisted indirect transition is observed in strongly confined nc-Si dots covered by oxide. # 2003 Elsevier Science B.V. All rights reserved.
Visible photoluminescence in amorphous SiOx thin films prepared by silicon evaporation under a molecular oxygen atmosphere
A simple reactive evaporation method is proposed to prepare light-emitting amorphous SiO x thin films. By evaporating pure silicon in a controlled molecular oxygen atmosphere, it is possible to obtain a very large composition range. By changing the pressure in the preparation chamber, x can be varied from 0.7 to 1.85. The composition and the structure of the films were investigated using energy dispersive x-ray, infrared absorption and x-ray photoelectron spectroscopies. The samples contain amorphous silicon clusters dispersed inside an insulating silicon oxide matrix. The room-temperature photoluminescence properties were then measured. By conveniently choosing the oxygen pressure, the as-deposited films exhibit visible photoluminescence without any annealing post-treatments. The luminescence intensity initially increases with excess silicon concentration and then disappears for a too-high silicon excess. The above effect is interpreted in terms of confinement of the amorphous silicon clusters in the insulating matrix.