SEMICONDUCTOR DEVICE PHYSICS AND DESIGN

534 APPENDIX C. DENSITY OF STATES

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 C.4: Energy dependence of the density of states in (a) three-dimensional, (b) two-
dimensional, and (c) one-dimensional systems. The energy dependence of the density of states
is determined by the dimensionality of the system.