We have investigated current-voltage characteristics of individual CdSe colloidal nanodots by conductive-tip atomic force microscopy (AFM). The colloidal nanodots were spun-coat and scattered on a self-assembled monolayer of thiophene molecules formed on Au (111) surfaces for single dot measurements. A thin SiO2 layer was deposited on the sample surface in order to prevent the dots being moved by the tip during measurement. We imaged the topography of isolated single dots by AFM operated in contact mode, and measured current-voltage characteristics with the conductive tip positioned on single dots; large conductivity changes which suggest resonant tunneling through a quantized energy level in the dot was observed even at room temperature.

We have fabricated submonolayer-thick films of CdSe colloidal nanodots in order to investigate electronic properties of individual nanodots by conductive-tip atomic force microscopy (AFM). Topographic and current images of isolated single CdSe colloidal dots on single crystalline Au (111) surface which was covered with dodecanethiol self-assembled monolayer were obtained by AFM operating in contact mode with a conductive tip under appropriate bias voltages. In the current image, it is found that the dot regions have higher electric resistances due to tunneling resistance through the CdSe dots. We also found 10 nm-scale electric inhomogeneity around the dots, which may corresponds to the previously reported etch-pits of Au (111) surfaces formed during the deposition of the dodecanethiol molecules.

The following theorem was published in [2].

Theorem. There exists a constant δ > 0 such that for Lebesgue almost every (α, β) ∈ X = [0, 1] × [0, 1], there exists no = no(α, β) such that for any n > no

where the integers pn, qn, rn are provided by the modified Jacobi-Perron algorithm.

This paper describes the processing of rare-earth/organic dye composites fabricated via three different sol-gel routes. In the first approach, low hydroxyl ormosil matrices were fabricated via reaction of a methyl-modified silicon halide with tertiary alcohol and subsequently doped with erbium iodide and a near-infrared dye. In the second approach, gels were made from tetramethoxysilane and doped with erbium complexes and dyes. In the third approach, a hybrid siloxane method was used. No Er3+ luminescence at 1.55 mm was observed in any of the three cases, mainly due to the strong absorption of the matrices centered around 1.4 mm. Fluorescence of Er3+ in the visible was observed in the first matrice, but no dye luminescence was detected. Dye luminescence was observed in the second type matrix, along with some reabsorption of the dye luminescence by Er3+. In the third approach, neodymium exhibited optical activity in the near infrared, as well as the dye.

We prove that there exists a constant δ > 0 such that for almost every pair of numbers α and β there exists n0= n0(α,β) such that for any n ≥ n0

where the integers pn,qn, rn are provided by the modified Jacobi-Perron algorithm.

Si samples, with and without masking oxide films, implanted with various doses of As, P, or BF2 have been evaluated on the formation of titanium suicides from titanium films. In all cases, suicide reaction for implantation with masking oxide films is more difficult than that for implantation without masking oxide films. Suicide reaction becomes more difficult with decreasing implant energy in the range over a critical dose. In the case of implantation with masking oxide films, knocked oxygen has been found at the surface of Si substrate. Suicide formation after removing the surface layers containing considerable amount of knocked oxygen with argon back-sputtering is as easy as suicide formation for implantation without masking oxide. The difficulty of Ti silicidation for implantation with masking oxide films is believed to be due to the effects of interference from knocked oxygen.