Jc. Vaissiere et al., SMALL-SIGNAL ANALYSIS OF THE BOLTZMANN-EQUATION FROM HARMONIC-RESPONSE AND IMPULSE-RESPONSE METHODS, Physical review. B, Condensed matter, 49(16), 1994, pp. 11144-11152
We present two original methods which yield the small-signal response
around the dc bias in bulk semiconductors, using direct numerical reso
lutions of the perturbed Boltzmann equation. The first method operates
in the frequency domain. An ac sinusoidal electric-field perturbation
superimposed to the dc field produces an ac perturbation of the distr
ibution function which is computed at each frequency. The second metho
d operates in the time domain. A step electric-field perturbation is s
uperimposed at time t =0 to the dc field. The resulting perturbations
of the distribution function and of the average velocity are then comp
uted as functions of time. These methods are applied to the case of ho
les in silicon at T = 300 K under hot-carrier conditions and are used
to compute the perturbed distribution function and the differential mo
bility spectrum.