EEE 309
Lecture-2
Ref: Principles of Electronic Materials & Devices by S.O.
Kasap (4th edition)- Chapter 4 & B.G. Streetman (Chapter 3)
3 H atoms
N H atoms
N atoms will cause the
energy level to split into
N levels
N is very large→ will
form a continuum of
energy states
N Si atoms
Metals, Semiconductor and Insulators
Effective mass of charge carriers
Same force different
accelerations!! →
mass different??
Effective mass
To the outside agent applying the force Fext, the electron will appear to be exhibiting a different inertial
mass, since its acceleration will be different. It would be most useful for the external agent if the effect of
the internal forces in Fint could be accounted for in a simple way, and if the acceleration could be
calculated from the external force Fext alone,
The effects of all internal forces are incorporated into m*e. It should be emphasized that m*e is obtained
theoretically from the solution of the Schrödinger equation for the electron in a particular crystal.
Can be experimentally measured as well → Hall effect is one such method