Length Scale of Diffusive Phonon Transport in Suspended Thin Silicon Nanowires.

Recent experimental advances have revealed that the mean free path (mfp) of phonons contributing significantly to thermal transport in crystalline semiconductors can be several microns long. Almost all of these experiments are based on bulk and thin film materials and use techniques that are not directly applicable to nanowires. By developing a process with which we could fabricate multiple electrically contacted and suspended segments on individual heavily doped smooth Silicon nanowires, we measured phonon transport across varying length scales using a DC self-heating technique.

Minimizing Self-Heating and Heat Dissipation in Ultrascaled Nanowire Transistors.

Through advanced electro-thermal simulations we demonstrate that self-heating effects play a significant role in ultrascaled nanowire field-effect transistors, that some crystal orientations are less favorable than others (⟨111⟩ for n-type applications, ⟨100⟩ for p-type ones), and that Ge might outperform Si at this scale. We further establish a relationship between the dissipated power and the electrical mobility and another one between the current reduction induced by self-heating and the phonon thermal conductivity.

In situ doping of catalyst-free InAs nanowires.

We report on in situ doping of InAs nanowires grown by metal-organic vapor-phase epitaxy without any catalyst particles. The effects of various dopant precursors (Si(2)H(6), H(2)S, DETe, CBr(4)) on the nanowire morphology and the axial and radial growth rates are investigated to select dopants that enable control of the conductivity in a broad range and that concomitantly lead to favorable nanowire growth. In addition, the resistivity of individual wires was measured for different gas-phase concentrations of the dopants selected, and the doping density and mobility were extracted.