Carrier scattering

One concern about any such treatment is that the donating or withdrawing group will form a new energy level (or distribution of levels) in the semiconductor. These energy levels may impact the device performance by scattering carriers or degrading the subthreshold slope. 

Table 4.1-80 Phonon wavenumbers of indium compouuds. Indium nitride (InN), T = 300 K indium phosphide (InP), RT, from coherent inelastic neutron scattering, carrier concentration n = 10 em indium arsenide (InAs), from Raman scattering indium antimonide (InSb), T = 300 K, from inelastic neutron scattering, carrier concentration n = SxlO cm ...

Hole-Optical Phonon Scattering Carrier-Acoustic Phonon Scattering... 

So, the resistivities due to various scattering mechanisms add, as well as the contributions to the conductivity from different carrier groups. 

Static defects scatter elastically the charge carriers. Electrons do not loose memory of the phase contained in their wave function and thus propagate through the sample in a coherent way. By contrast, electron-phonon or electron-electron collisions are inelastic and generally destroy the phase coherence. The resulting inelastic mean free path, Li , which is the distance that an electron travels between two inelastic collisions, is generally equal to the phase coherence length, the distance that an electron travels before its initial phase is destroyed ... 

In the presence of weak disorder, one should consider an additional contribution to the resistivity due to weak localisation resulting from quantum interference effects and/or that due to Coulomb interaction effects. A single-carrier weak localisation effect is produced by constructive quantum interference between elastically back-scattered partial-carrier-waves, while disorder attenuates the screening between charge carriers, thus increasing their Coulomb interaction. So, both effects are enhanced in the presence of weak disorder, or, in other words, by defect scattering. This was previously discussed for the case of carbons and graphites [7]. 

In delocalized bands, the charge transport is limited by the scattering of the carriers by lattice vibrations (phonons). Therefore, an increase in the temperature, which induces an increase in the density of phonons, leads to a decrease in the mobility. 

As evidenced by their low abundances, carbon compounds, water, and other volatiles such as nitrogen compounds were probably not significantly abundant constituents of the bulk of the solids that formed near the Earth. Many of the carriers of these volatiles condensed in cooler, more distant regions and were then scattered into the region where the Earth was forming. Eragments of comets and asteroids formed in the outer solar system still fall to Earth at a rate of 1 x 10 kg/yr and early in the... 

In addition to the photoluminescence red shifts, broadening of photoluminescence spectra and decrease in the photoluminescence quantum efficiency are reported with increasing temperature. The spectral broadening is due to scattering by coupling of excitons with acoustic and LO phonons [22]. The decrease in the photoluminescence quantum efficiency is due to non-radiative relaxation from the thermally activated state. The Stark effect also produces photoluminescence spectral shifts in CdSe quantum dots [23]. Large red shifts up to 75 meV are reported in the photoluminescence spectra of CdSe quantum dots under an applied electric field of 350 kVcm . Here, the applied electric field decreases or cancels a component in the excited state dipole that is parallel to the applied field the excited state dipole is contributed by the charge carriers present on the surface of the quantum dots. 

Poorly absorbed compounds have been identified as those with a PSA>140Af Considering more compounds, considerable more scatter was found around the sigmoidal curve observed for a smaller set of compounds [74]. This is partly due to the fact that many compounds do not show simple passive diffusion only, but are affected by active carriers, efflux mechanisms involving P-glycoprotein (P-gp) and other transporter proteins, and gut wall metabohsm. These factors also con-... 

Size and homogeneity of liposomes are important in their use as drug carriers, since these characters affect the pharmacokinetics and distribution of liposomes in vivo. Light scattering, electron microscopy, NMR, and gel filtration are used for evaluating liposomal size and homogeneity (32,33)... 

---