Titanium catalyzed silicon nanowires and nanoplatelets

Abstract

Silicon nanowires, nanoplatelets, and other morphologies resulted from silicon growth catalyzed by thin titanium layers. The nanowires have diameters down to 5 nm and lengths to tens of micrometers. The two-dimensional platelets, in some instances with filigreed, snow flake-like shapes, had thicknesses down to the 10 nm scale and spans to several micrometers. These platelets grew in a narrow temperature range around 900 celsius, apparently representing a new silicon crystallite morphology at this length scale. We surmise that the platelets grow with a faceted dendritic mechanism known for larger crystals nucleated by titanium silicide catalyst islands

Coupled mechanical-oxidation modeling during silicon thermal oxidation process

“…A confusing phenomenon in the experiment of Lin et al 36 is that uniaxial stress of 10 MPa has an even stronger effect than that of 15 MPa, which is still need to be verified. In contrast, other experimental results 5,33,34 indicate that a heavier load leads to a stronger effect.…”

“…This is different from lots of experimental results in which tensile strain loads have a promoting effect. 5,31,33,34 As seen in Fig. 7(a), scale thickness under tensile stress load is still generally higher than that under compressive load, indicating that the oxidant diffusion process is actually accelerated by tensile loads.…”

“…This theory was also followed by Navi et al, 23 Noma et al 24 and Delph et al 25 Meanwhile, Irene et al 8,[26][27][28] investigated the effect of stress on reaction rate constant and suggested that the reaction rate at the scale/substrate interface was proportional to the magnitude of compressive stress in the scale. Kao et al 5,29 and Sutardja et al 30 investigated the two-dimensional thermal oxidation of silicon. Due to the stress effect, the oxide grown on a concave surface was much thinner than that grown on a convex surface.…”

“…Owing to its great importance in technology, [1][2][3][4][5] the formation of silica layer by silicon thermal oxidation has been extensively studied in the past few years. Differing from the widely accepted parabolic law, the subsequent experimental results indicated that the exponent value was always in the range between 1.0 and 2.0.…”

Electronic bandstructure and optical gain of lattice matched III-V dilute nitride bismide quantum wells for 1.55 μm optical communication systems

“…It has been found that, in GaNBiAs semiconductor alloy, when the N : Bi composition ratio is 0.58 we can obtain lattice matching with GaAs 5 . Co-alloying N and Bi opens up avenues for bandstructure engineering and precise strain control in the GaNBiAs quaternary alloy 6 . In dilute-Bi alloys, the a) Electronic mail: sumanta001@e.ntu.edu.sg b) Electronic mail: edhzhang@ntu.edu.sg bandgap reduction is caused due to coupling between Biresonant state and the valence band (VB) state; while on the other hand, in dilute-N alloys, this effect is induced due to N-resonant state coupling with conduction band (CB) state 7 .…”