Fundamentals of Carrier Transport, Second Edition
Including many homework exercises and a variety of worked examples, this book is an accessible introduction to the behavior of charged carriers in semiconductors and semiconductor devices.
TABLE OF CONTENTS Fundamentals of Carrier Transport, Second Edition
2.3: General Features of Phonon Scattering
2.3 General Features of Phonon Scattering
The general features of phonon scattering are easy to describe and understand. In this section, we describe the general characteristics of the most common types of scattering.
2.3.1 Scattering from a static potential
The simplest model for a static perturbing potential is a ?-function
| (2.30a) |  |
As shown in Section 1.7, this perturbing potential leads to a transition rate of the form
| (2.30b) |  |
which, as shown in Section 2.1, produces a scattering rate that is proportional to the density of states,
| (2.30c) |  |
This basic result, that the scattering rate is proportional to the density of states, is a common feature of carrier scattering. The more states at a given energy, the more ways a carrier can scatter to it. The ?-function approximation is a useful approximation for highly localized, static scattering potentials.
2.3.2 Nonpolar phonon scattering
A second common scattering potential is the oscillating potential produced by lattice vibrations. This potential can be written as
| (2.31a) |  |
where A ? is related to the amplitude of the oscillation and K ? to the deformation potentials discussed in Section 2.2. As shown in Section 1.7, this type of perturbing potential leads to a transition rate of the form
| (2.31b) |  |
where the ?-function expresses conservation of energy and the Kronecker ? conservation of momentum.
In Section 2.5 we will demonstrate that the requirement that both energy and momentum be conserved restricts the phonons that can be involved in intravalley scattering processes...
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