SEMICONDUCTOR DEVICE PHYSICS AND DESIGN

2.3. ELECTRONS IN CRYSTALLINE SOLIDS 35

N(E)

N(E)

E–1/2

1D system

E

(a)

E1/2

N(E)

3D system

E

E^0

2D system

E

(b)

(c)

V 0

V 0

V 0

Figure 2.3: Energy dependence of the density of states in: (a) three-dimensional, (b) two-
dimensional, and (c) one-dimensional systems.

on the physical property being characterized. Appendix C describes the various forms of effec-
tive mass in detail. The expressions derived for the free electron density of statescanthenbe
carriedovertodescribethedensityofstatesforaparticleinacrystallinematerial (whichhasa
periodicpotential)bysimplyreplacingm 0 bym∗.