Temperature dependence of silicon carrier effective masses with application to femtosecond reflectivity measurements

Abstract

The conductivity effective masses of electrons and holes in Si are calculated for carrier temperatures from 1 to 3000 K. The temperature dependence of the electron mass is calculated by use of a phenomenological model of conduction-band nonparabolicity that has been fitted to experimental measurements of the dependence of the electron conductivity effective mass on carrier concentration. The hole mass is investigated by tightbinding calculations of the valence bands, which have been adjusted to match experimental values of the valence-band curvature parameters at the top of the valence band. The calculations are in excellent agreement with femtosecond-laser reflectivity measurements of the change in optical effective mass as hot carriers cool from 1550 to 300 K.

Photo-designed terahertz devices

“…The optical pump power ( P pump ) was varied from 4 mW to 100 mW, which gave a corresponding carrier density at the Si surface ( N pump ) of between 1.1 × 10 16  cm −3 and 2.7 × 10 17  cm −3 , and a plasma frequency ( f p ) of between 0.7 THz and 3.4 THz. These values were calculated using the relationship f p = ( N pump e 2 /ε 0 ε Si μ) 1/2 , where 1/μ = 1/ m e + 1/ m h is a function of the reduced masses of the electron and the hole, m e = 0.27 m 0 and m h = 0.37 m 0 are the effective masses of electrons and holes in Si15, ε 0 is the permittivity of free space, ε Si = 11.6 is the permittivity of Si in the THz frequency regime, e is the electron charge, and m 0 is the electron rest mass.…”

Microscopic origin of the Drude-Smith model

“…A mass of m * = 0.26m e is used for the simulations, which is the electron effective mass in silicon. 78 The velocities of the individual particles are combined to find the net velocity, and hence the net current, at each time step. In the y-direction, current oscillations are driven by the electric field, while the current in the x -direction provides a noise estimate.…”

Hole injection and dielectric breakdown in 6H–SiC and 4H–SiC metal–oxide–semiconductor structures during substrate electron injection via Fowler–Nordheim tunneling

“…where m à c and m à v are the temperature dependent [24] conductivity masses of electron and hole in Si, respectively. E g;Si is the bandgap of polySi and is a function of both temperature [20] and doping concentration [25].…”