Physica 134B (1985) 169-173
North-Holland,Amsterdam 169
MONTE CARLO ANALYSIS OF HOT-PHONONEFFECTS ON NON-POLARSEMICONDUCTOR TRANSPORTPROPERTIES
Paolo BORDONE, Carlo JACOBONI, Paolo LUGLI, Lino REGGIANI
Dipartimento di Fisica e Centro Interuniversitario di Struttura della Materia dell'UniversitA di
Modena, Vie Campi 213/A, 41100 Modena, Italy
Peter KOCEVAR
Institut fur Theoretische Physik, Universitat Graz, Universitatsplatz 5, A-8010 Graz, Austria
An iterative procedure to include phonon disturbances into a Monte Carlo algorithm is presented.
Low temperature transport in p-Ge is considered. Calculations show that carrier drift velocity and
mean energy increase as a result of the phonon amplification.
I . INTRODUCTION
The inclusion of phonon disturbances into
calculations of the electrical or optical
response of a semiconductor represents a still
widely unexplored area of nonlinear transport
theory. When an electric field E is applied
to a crystal, it feeds energy and momentum into
the free carrier system. In contrast with the
thermal equilibrium case of equal phonon
emission and absorption rates per carrier, a
field induced emission sets in and the phonons,
which are stronply coupled to the carriers,
become amplified. Noticeable effects of such
phonon disturbances on transport coefficients
can be expected under the following two
conditions: (i) the carrier system has to be
far from equilibrium; (ii) the lifetimes of the
electronically-active phonons must be
comparable or longer than the characteristic
times for their field-induced built up.
Accordingly, we consider only disturbances of
the first phonon generation created directly by
* Partially supported by Ministero Pubblica Istruzione
the carriers. We neglect the amplification of
the second and later generations, resulting
from the decay cascade of the initally excited
phonons, as they do not couple effectively to
the carriers.
Because of the computational complexity in
the evaluation of a coupled nonequi~ibrium
carrier-phonon system, almost all hitherto
published attempts used a heated Maxwellian in
a diffusion approximation or assumed a ileated
and displaced Maxwel I i an (or Fermi )
I-5
distribution of the carriers
some predi cti ve power,
carri er-temperat ure model s have
known limits. Since the Monte
technique
solutions
of this
step, in
inclusion
An iterative self-consistent procedure that
combines a MC calculation for the electronic
and Centro di Calcolo dell'Universit~ di Modena
Although of
these
their well
Carlo (MC)
provides a more general approach to
of nonlinear transport 6, the purpose
contribution is to establish a first
a long term project, toward the
of phonon disturbances into MC codes.
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(North-Holland Physics Publishing Division)